as a former spec v owner that was on engine #3 and tranny #2 when it sold, i feel your pain. luckily, all my repairs were under warranty. the QR25DE is a rock solid engine (outside of the 2002/2006), but the damn precat breakup and butterfly screw issues cratered it. i had to run a stock setup for autox, so that's why i had recurring problems. but you should be able to find a good-running 03-05 QR25DE shortblock for $600-$800. drop that in, gut your pre-cat or get a cat-less header, loctite those butterfly screws in the intake manifold, and your engine should be fine for a looooong time. or if you're in an emissions free state, talk to travis and do a VQ swap. he'd also be a good guy to contact for a used QR25DE block - he used to have a lot hanging around his shop.
i definitely feel your pain
