Dang dude, jump on that deal! Neither one of you are coming out ahead in particular (okay, maybe the R owner is just a bit), but if the both of you are comfortable with that type of trade, go for it.

Your car is worth what, about $28k to $30k w/ the miles you have? The springs, body kit, swaybars and rims cost you about $6k-$7k I assume? The Type R is still worth about $20k-$21k, a JDM front end conversion w/ labor is about $4k, 17" Volk TE-37 rims are about $3k or so w/ tires (prolly cheaper now).