Need help with tire set up
 

I just purchased my first Scion FRS and I am dissatisfied with wheels that came with it. I bought it used so it already has mods done such as it’s lowered on coils. Right now I’m on 225/35 and the wheel I believe is 20”. I went to a shop today and guy suggests 18x8.5 with 225/40/18. He’s offering me new tires and wheels (rotiform) for 1250. Should I accept this deal? Is this a good set up?

I can't speak to the quality of the wheels, but the quality of the setup is going to depend entirely on what you want from the car. Questions to ask here:

What specifically don't you like about your current wheels? The looks, the ride, etc? If looks, that's all up to you. However, a smaller wheel with a larger tire sidewall will definitely improve the ride quality a noticeable degree. Since you are already lowered on coilovers, this would be a nice result for a (I assume?) daily driver.

Which rotaforms are they offering? I'm not really familiar with them, but here's a quick read I found http://www.speedhunters.com/2016/10/the-rotiform-story/

What brand and model of tires are they offering?

Blue's got some good questions. 20" wheels....not sure I'd stick with that either. I purchased the Apex ET42 ARC-8 BRZ/86 wheels (17x9), and absolutely love the fit and look. Great fender clearance with the 245's on it. They may even still have the current sale in effect. I think I paid about $250 per wheel before the current sale.

The search function works well in this website, I'd try it.