Future maybe yaris owner!

[lk250f]

Hello, this is my first post here. My name is Landon and i drive a 2007 Honda Civic Si right now but took interest in the Yaris hatch. Im going this weekend to look around for a manual trans hatch. Anything specific to look for? I know its a downgrade in many ways but i want something simple and that runs on reg gas too. My only plans are to do coilovers, set of 15'' wheels(not sure what kind yet, suggest some please) and just small cosmetics plus maybe a trd exhaust. I want something different, more fuel efficient and that's cheap to mod. I was looking into tein basics for it, but any other good coil brands? Thanks for all the help, i just wanted to introduce myself. Most questions will probably be answered by the time i read through the forums lol. thanks. P.S: What is the most wide wheel i could get with the stock tire. I think theyre 5.5 wide stock, so maybe a 6 or 6.5 tops? I dont want the tires too stretched. Thanks much!