Leaderboard

Q1. No, no gains, if anything you will slightly _lose_ as the aftermarket rods and pistons are potentially heavier, less well balanced, and not quite as good a fit as OEM. Assuming identical geometry, i.e. not gaining/losing compression. Stock turb and intercooler are never going to push the limits of even the stock internals if everything else is happy. Q2. I wouldn't bother just doing one. Either it's a forged build or it isn't. As to whether you would replace the pistons.... if you buy used pistons, you have no idea of their history. If you buy new pistons they're going to cost you about $500 for a set for stockies, is it worth it? I'd say probably not. Q4. The only factory internals I'd consider an "upgrade" are V7 STI EJ207 pistons and rods, and they're >$2000 for the pistons and around $800 for a set of rods, at which point you may as well just go aftermarket. Q5. Head gaskets, OEM. Rebuild kit in terms of bearings? YMMV. OEM are probably going to be the most reliable at stock power levels but might cost a metric assload. Q6. Yes, it's fine. Honestly unless #racecar where you have specific oil pressure needs, dicking about with the oil pump seems to lead to more problems than it's worth. Q7. As long as you weren't way out I'd probably nana it to the tuner, especially if you had slightly dropped compression rather than adding it. As long as you were comfortable it was driving well enough to make that trip safely. Anything turbo is kinda fundamentally variable compression anyway because the actual resultant cylinder pressure could be just about anything. With that out of the way.... I wouldn't bother with a rebuild to factory spec. A better option, IMO, is to just keep driving it on the assumption it will blow up at some stage, and in the meantime get another block and start building that one up properly (forged etc). Then when yours finally gives up the ghost, you have the option of throwing in a bigger turbo or something and making a bunch of power.

I'd totally agree with what boon has said. I'd likely steer clear of what you are wanting to do regarding rebuild and address at the time. You'd spend a lot of time (and money if you make a mistake) just to get it to a position where you wanna do the basics to the platform. You'd wanna go big or go home if you're talking ripping into the engine and not just swapping with a donor engine. If it were me with 180ks on it, I'd just do the bolt-ons like you have suggested and keep up with services (plus the tune). Keeping on-top of maintenance plus a good tune will give you the best chance on these cars. The cars really wake up with the downpipe, exhaust, fuel pump, 3 port and a tune. I've done exactly that to mine, plus some handling mods, and it's such a nice car to drive compared to stock. Only thing I wish I could do would be coilovers instead of lowering springs but I cbf with a cert or swapping them out for wofs lol

The software looks nice. The base maps they have loaded in are super informative and it looks like they have the twin turbo system and definitions all figured out. Any competent tuner could work with this.

@JordanfromNZ if he is around...