lol, my wrx got 97k on it and its running a big 16g setup, just got a compressiont test and all cylinders are 150. (good as new) I think 1 in every 15 subaru has a defect in the engine. I have seen sti stock piston go out under 20k without mods, maybe my wrx is one of the lucky 14 that made it out perfectly. But if you go to google shopping you can find a brand new sti block for under 2000 and a built one with piston for under 4, google is better than ebay when it comes to shopping, it even show you ebay items on there too and every online shop that is selling the part your looking for. If i was you i would go with the 2.5 swap, plus the hybrid wrx put out more torque than the sti on stock heads. but im switching to the sti for the brakes, avcs and other stuff the wrx dont have.