Why are people searching for "vn b m gn mbnmncbm xbc bcv 0 vfkmjirhtfnkj nb b x bmnx bv"?

I have no idea. But Microsoft's AdCenter seems to think it's an excellent phrase to advertise against!
(According to The Register)

Mario Kart Wii - how do you get 3 stars? (part 4)

Update: Part 1, Part 2, Part 3

I'm actually running out of advice now! Please bear with me if you already know any of the advice in the tips below. I hope I still have some surprises up my sleeve!

Marv's 14th tip - you can sometimes avoid a blue shell
Don't get too excited by this one, but it is possible to occasionally avoid a blue shell. However, in 99% of cases, you are screwed.
The main method of avoiding the blue shell is to be going through a cannon, which obviously only works on those courses with a cannon/"big jump" (DK's Jungle Parkway [I think], DK Mountain, DK Summit, Maple Treeway, etc). This is difficult to plan - by the time you hear the dreaded blue shell warning siren, if you're not about to go into the cannon anyway, you'll be hit! It's nice when it happens though.
You can also avoid a blue shell by jumping off the track into space or deep water on those levels that have them. This generally wastes more time than it saves, so is only really worth it if you're playing against a friend and want to deny them the satisfaction of actually hitting you!
There is a way to avoid a blue shell on-demand, but you have to have at least one boost mushroom. Since I'm assuming you'll be in 1st place for most of each race, getting a boost mushroom is tricky. I guess if you find yourself further back in the pack and get a mushroom, it might be worth holding onto it for a while.
Assuming you manage to get a mushroom, the idea is to use it as soon as the blue shell stops moving around your vehicle and starts to dive down. There are various videos on Youtube, including this one. Apparently, the time-frame for using your mushroom is longer than in Mario Kart DS. I tried this method once, accidentally using two mushrooms instead of one, and did manage to escape unharmed. Good luck!
(You can also avoid a blue shell if you have an invincibility star, I believe - and possibly a bullet-bill. I have a feeling that a mega-mushroom won't help. All of these are power-ups you are unlikely to have in 1st place!)

Marv's 15th tip - hang back slightly on the first course
The further back you are in the pack (i.e. the worse your position), the better power-ups you will get. This isn't much use when your aim is to get to 1st place and stay as far in the lead as possible. However, there's one occasion in each Grand Prix where you can't help being further back - when you start your first race.
So, rather than trying your best to get to the front of the pack, you can fight your way forward, but only to something like 6th - 2nd. Stay back until you go through the first set of question-mark blocks. As soon as you are past, start playing harder to get to first place. With any luck, you'll have picked up a better power-up than if you'd been in first place when you collected the question-mark block.
There are some courses where this works better than others. For example, there are courses where the question mark blocks are quite close to the starting line, and it's difficult to get to the front anyway. Those courses are good candidates for this tip. However, there are other courses where you have to drive for a fair stretch before you get a power-up, and still others where there is a good opportunity for over-taking and getting a good lead. On those courses, this tip isn't so useful.
You can also use this to your advantage if you are hit by a particularly nasty set of items and end up in 2nd-or-worse place. Hang back just slightly to get, hopefully, something like a star or 3 mushrooms to help you back into 1st with a decent lead! Be wary, though. Sometimes you'll get something like 3 green shells, which isn't really worth hanging back for!

Marv's 16th tip - use drafting
Like some of the other tips I've written, this is one from the instructions manual, but one that many people aren't aware of.
Not to be confused with drifting, drafting is a technique you can use where if you are driving (closely enough) behind another character you will see wisps of smoke/steam/who-knows from your vehicle; you will also get slightly faster. If you manage to stay directly behind that vehicle for long enough, you will see a sort-of white tunnel of air wisps, which gives you a further speed boost, and normally means you can knock the car in front out of the way!
This is mostly useful at the beginning of the first race, if you do want to take the lead quickly. Also if you happen to fall behind. It's probably worth knocking the vehicle in front if you can - any extra distance you are in front helps!

Marv's 17th tip - stay on the main part of the track
Again, this might be obvious, but it might not be! There are many places where you can take short-cuts, some of which may look very inviting. In general, however, any short-cut that means you'll be driving off the main part of the track may well slow you down enough that you will lose more time than you gain.
For example, in Delfino Square, there's a little alley you can take after the small bridge and before the big rainbow lifting bridge. But if you take this short-cut, unless you have amazing power-slide turbo skills you get slowed down massively by the mud.
You can take these short-cuts if you manage to snag a mushroom (or a star if you're very lucky!), as long as you aren't planning on saving it to battle a blue shell.
Other short-cuts may be less drastic, but still slow you down - driving over grass, sand and water is generally slower.
There are shortcuts, however, which do save time - like on Wario's Gold Mine. The difference there is that the road surface does not slow you down (in fact, there are boosts) and so, as long as you don't hit anything, you can shave valuable seconds off your time!
If you want to know which shortcuts are good, I would recommend downloading the world champion records for each lap (ignoring any shortcuts that use mushrooms) or hitYouTube and look for good times! Do bear in mind that some vehicle/character combinations will be better at some shortcuts than others.

Marv's 18th tip - be lucky! Or patient...
No matter how good a driver you are, sometimes you just will not be able to win. I recently played through the Special Cup and was hit by no less than 6 blue shells onBowser's Castle Wii . And that was on 50CC! While I managed to grab 1st place, the amount of time I had spent catching up meant that I didn't get a 3 star rating.
So ... accept that sometimes you will be unlucky, and sometimes you will be lucky. If the same thing happened every time you played a GP, it would be boring anyway!
If I have a bad race in the middle of a GP, I normally tend to continue, reasoning that getting practise in the remaining races is no bad thing. However, if my first race goes badly, I do occasionally throw in the towel and start again!
Remember - the important thing is to have fun.

Well, that's me done for now. As you may have noticed, I'm running out of information that I can pass on, so this might be my last post. Thank you for reading, and thank you for your comments! If you guys 'n' gals do have any other questions or comments, please feel free to add them, and if I get enough stuff together, I might do another post. There's also a chance I might scour the web for more information to put here!
I did contemplate doing a breakdown of how to play each race, but that would be quite time-consuming, and I'm not sure how useful it would be! Again, if any of you are stuck on a particular track or GP, let me know and I can create a sample breakdown or two.
Good luck, and enjoy yourselves. Hope to meet some of you on WiFi at some point!