I don't believe you need to raise compression to use Skunk2 cams. You'll get more hp with higher compression, hell you'd get that with your stock cams, but I don't think it's nessicary. I remember reading a test with a B18C1 (I want to say Turbo magazine but I don't remember, it was a while ago) of Type R cams vs Skunk2 stage 1's I think (both using the appropriate valve springs) and the Skunk2 was better across the board. I think you'll be able to hit 13's with a new set of cams and maybe a little time on a dyno with a fuel tuning computer (like a V-AFC).