good day. i currently have a celica convertible 6 generation all stock. but i want to change my tires from stock to 18" rims. i have stock springs and suspensions. my question is what rims will fit without doing any modifications? is it 18x7, 18x7.5, 18x8??? and for the tire size is 225/40/18 will fit fine without hitting anything??? thanks

1010tires.com has a nice tire size calculator that lets you compare 2 or more tire sizes, and they also have a wheel offset calculator to help decide how wide of a rim will fit.
http://www.1010tires.com/WheelOffsetCalculator.asp
http://www.1010tires.com/TireSizeCalculator.asp

also this
http://www.6gc.net/forums/index.php?showtopic=69919

tnxs guys!