They exist... just google "7mge stroker kit" (or "7mgte stroker kit" if you have a turbo).. here's the first one I found, sure there's some cheaper...
http://www.importperformanceparts.ne...s_toyota2.html
however, from the spec's mentioned, I'd imagine you'll want to up your injectors and possibly your fuel pump and rails (but not sure bout that). However, if that's done in part of the kit, no worries.. Good luck, I'd love to get that much power out of my supra... atm, I think I'm gettin somewhere around 180-200hp :\.. but she's in no condition to dyno, still pretty much stock with quite a bit of sluggishness..