i want different rims but i dont know what i should buy and suggestions looking for something cheap, looks sweet, and also im looking for 18'' with tires so if any one knows a good site or even a good package let me know
well, it depends. #1 concern should always be weight if you're concerned about performance. logically, a bigger wheel will weigh more. of course, exceptions to this can be found since wheel design, manufacturing process, and material selection all come into play. in general, though, you'll find it a lot easier to find smaller rims in lighter weights.
if all you're concerned about is looks (which is fine IMO), then go for the 18s. i think they look too big, but i know some people like that look. also, remember that a rim that big leaves less room for the tire around it, esp. if you have a drop. this means that you run the risk of a harsher ride as well as a heightened possibility of denting your rim. the higher profile the tire, the better.
as far as speedo calibration and all that stuff, i'll send a link when i get home that has a calculator so you can see the difference between what you're speedo reads now and what it will read with bigger tires. 205/40/17 won't give you the EXACT same readout, but it's pretty darn close (less than 2% difference if i remember right)