It depends on weight, width, and tires. If you have a light but STRONG rim...18x8.5 and good tires, you'll be doing pretty well.
Less side wall to for BETTER cornering.

-freddie

 

hey there

well, weight would be the first issue i can think of. a heavier wheel will make the suspension work harder, and creates more unsprung weight. for example, a heavier wheel will cause the suspension to work harder over the crappy bay area pot holes. a lighter wheel will require less effort to control thru the travel of the suspension, which equates to a the tire remaining in contact with the road which equals better handling. a heavier wheel also makes the motor work harder throughout the entire power range, and you can loose performce in the places you want it most (exiting turns, etc)

a 18" wheel will however have a narrow sidewall'ed tire, which in theory should flex less, and provide better handling (more precise at the expense of more vibrations and noise). but the tradeoffs can outweight the benefit.

subaru's are well known for the great travel their rally bred suspension offers. many like to lower their cars, thus reducing travel. they also usually run god awful high spring rates and compression/dampening rates which leads to a terrible daily ride. sure it is great for the track, but how many of us really frequent the track weekly? for the auto-xer, it makes sense, but even then, a softer more compliant suspension generally handles better. no one likes body roll and a flat handling car "feels" faster, but in many cases it does not.

back to the main question..... if you look at the fastest impreza's around the world, most run 17" rims as wide as the fenders can handle. the wider tires make a big difference in handling. the extra sidewall can help offset a stiffer suspension and also protect those $2.5k lightweight tires and rims from being destroyed by a pot hole. they are just more practical. BUT, 18" rims do look pretty good, and do improve handling over the stock rim/tire set up.

if you aremore about the looks, and a bit of improvement in handling, go for the 18"'s. if you are looking for the best performance, its hard to beat a good 17" set up (heck, most auto-xers use 16 or even 15" rim).

josh

 

hahaha
I go through those fazes ALL THE TIME!!!!
Have fun...it will look sweet with either rim.

Good reply Josh!
Thats exactly what I meant to say....hahaha
-freddie

 

hell yeah keep the te37's... great rim and strong as hell...

i know exactly what you mean. it is the disease we all have called moditis. i am going thru donthaveacaritis at the moment, and cant wait to jump back in the game.

josh