Let me just say first that i did a search and i found tons of posts. I just found it way to much to read and thought this is a much better way to get a direct anwser.

I went to CJ Tires near my place and i was all ready to buy some 17s for my 01 legacy. The guy behind the counter said i should stick with 15s because I might have some "performance issues" if i go any bigger. Now im the type of person that thinks rims make or brake a car. This is is the first car i ever owned with hubcaps i hate thew way it looks. But i feel that if im going to spend time and money on getting new wheels then i want something that I will like and will look good. Now i think they don't work on commision so I thanked the guy for his honesty and said i will be back (after i talk to you all). Is he telling me the truth, will i have problems even if i go with 16s? Please give me your feed back, thanks.

 

The "performance issues" he speaks of is the better handling you will experience with smaller sidewalls. But along with that comes diminished ride quality. The smaller sidewalls will let you handle better (less flex when cornering), but the tires won't absorb as many bumps. It's definitely a trade off, but well worth it in my opinion. Oh, and make sure you get the correct offset wheels so the tires don't rub. Good Luck!

 

That guy is an idiot. The ride will be a little stiffer with a low-profile tire. But 17s really aren't too wild. The "performance" of the car will most likely increase due to the increased grip (if you get good tires) and decreased sidewall flex during cornering.

 

The previously posted info is right on. There are naturally a few ups and downs to every change. In comparing the same tire, the larger the rim size the rougher the ride. I personally haven't noticed any difference between 16 and 17s on my car. The benefits, however, are numerous. Better look, cornering response, traction, etc.

In general, upsizing is good. Just make sure you do it correctly with the correct tire/wheel sizes.

 

I have a '02 Legacy and I put a set of 16" stock RS wheels on it. I haven't noticed any performance loss (in fact, its a might bit better because the 16" stock RS wheels + tires are lighter then the steel wheels I had on before).

I'm contemplating 17" wheels soon too. I don't think there is a downside.

SOUtHSPOkEN:
18" will more then likely be a little heavier, so your acceleration may be slightly affected, but other then that I can't see a problem. My buddy has 18"s on his STi and he hasn't complained about a thing yet (although I don't think he does many donuts).

 

Off road + 18s = bent rims. Guaranteed. In fact, it probably wouldn't be that hard on 17s. I wouldn't do it in my STi... if I had one.