currently looking at maybe putting some 17x8 17x7 rims on my tr magna. will they fit. currently running r32 gtr 16in mags with 5mm spacer.

spacers are definately NOT legal..
according to RTA. you can go 2 sizes larger ( 15" --> 17" ) and 1 " wider than the maximum recommended wheel and tyre combination ( as indicated on the tyre placard )
as long as your rolling diameter does not increase too much. (speedo will go way out)
also wheels can't potrude from vehicle and your distance between the centre of the tires IE front-left-centre to front-right-centre can't increase more than i think 12mm.
check up the RTA website :P that will be much easier (just search for rim sizes and download
the .PDF file ( i would do it for you but i couldn't be bothered)
cheers

i have 17x7's and they rub at full lock on splash guards, when dumping clutch too early spins into second probs chirp 3rd; burnouts are ghey; i wouldnt get much traction with stock 15x5 and i dont have much power; i want 18x8's

oh and my speedo is spot on what speed im doin; stock they set it behind so you dont get caught out

I've got 17x7's. They do hit the splash guards at full lock. But that's an easily fixed problem.