So i have a prelude and plan on turboing it around march or april next year, and just bought some 18" motegi touge wheels. I was going to get some 17" for the front but they only make 17 x 9 in those wheels and thats too wide for my car. My question is will the 18" x 7.5 cause a significant power loss? They are a heavy 25 lbs. but i'm kinda 50/50 on looks and performance, looks are about as important but i dont wanna lose a whole lot of power either. Any thoughts?

Its a matter of physics....no its not going to "decrease" power, but it will effectively make your gearing longer and increase the amount of rotational mass which will make it harder to start from a stop AND stop when rolling.

By the way, if you're looking for a turbo setup for your Prelude, my buddy Eric has a complete Drag setup for sale. It was used for one season....food for thought