Originally Posted by holyjoetart
The 05 and 06 legacy gt short block is the same as an Sti SB. The heads are the big difference between the legacy and the Sti.
Heads,cams, valves, valve covers, plugs, wires, coils, oilpan,oil pump, waterpump, timingbelt, timing belt covers,exaust mainifolds, mid-pipe, up pipe, alternator, p/s pump,water neck, thermosatst and if I'm not mistaken the injectors are yellowtop side feed sti injectors... all these are the same as the Sti down to the tensioners.
(Same part numbers)
The diffrences that I have gathered are, diffrent up pipe, turbo, wastegate, intercooler,intake manifold, the airfilter intake, maybe the tgv's(but I don't think so) throttle body and some cooling and vacum line routeing under the intake, but the wiring harness on your lgt/obxt should be the same.
The fuel rail might be a little diffirent, I do recall reading something about that, but I'm not positive. I tore down my obxt engine today, its all pretty fresh in my head.
The intake on the lgt/obxt it plastic, logicly this means it will retain less heat, and since its moldedplastic my bet is it thinner and capable of flowing better than a sti intake. The Sti intercooler won't fit under the hood of a lgt/obxt with out modifing you scoop. All and all unless you just want to pop your hood and see Sti on your intercooler and a red intake, its really not worth all the work. With a d/p, turbo, intercooler and a tune you would be 300ish hp just as easyy as the "Sti engine"