i have a 91 ls400 and plan on getting some wheels for it. i want a good size that looks great on the car without having to lower it. i want to keep the ride quality. so what size is best? im not to familiar with off set and all that other stuff. so some help would be much appreciated.

go with 18 i have 17 on my 91 Ls400 it looks small

you got a picture of your car?

I would recomend 17 inch with 225/55 tires. Have that on my car and I'm very pleased with this set up. For pictures see this post:
https://www.clublexus.com/forums/ls4...400-ucf11.html

go with a staggered set of 18's. preferably not chrome. if you're not lowering it, offset won't really matter so donw't worry too much about that. 225 40 18 up front and 265 35 18 in the back.