You will need something a lot better than the PMBS upgraded factory option for circuit use.
The moroso or Killerb sumps are the cheapest first step. I have the moroso sump and still get some surge.
Something else super important for circuit is keeping oil temps down. You want to lock them to 85-90C or the oil viscosity thins out massively and worsens the pressure issue exponentially.
You might want to check the ECU doesnt also run the auto transmission. Doing a manual conversion is mechanically simple enough but electrically impossible if the ECU also runs the trans like it does on newer models.
For the $ and that sort of power I'd rather do a ej207 and ecu swap. The modern engines with AVCS are so much better than the v4 engines... Even a v4 engine with an ecu, injectors, turbo and tune for ~240kw is going to have way less midrange than a well sorted version 8-10 engine that can achieve the same power.
there can be small differences in avcs cam timing between banks due to belt stretch, lower block deck heights and oil pressure differences. But the valves would have hit happened the first time the cam timing was advanced on the dyno, your engine ran for a while first...
Leaking fuel injector maybe. I had a lower injector seal blow out on the motorway and boost wouldnt go under 5psi the rest of the way home
You'll have top feed injectors though so one would have to be stuck open by some debris...
Brakes arent an issue with swapping to 5x114 hubs (v9+ STI), brake discs will need to be redrilled or replaced but the caliper mounts are the same so your current stuff should swap straight across.
Suspension strut clevis is wider but it can easily be milled down and the top hole welded up and a new hole drilled. Not complicated...
Actually the last cylinder is closest to the FPR and therefore has the most consistently regulated fuel pressure. The firing order is cylinders 13 then 24 which by no coincidence (imo) is the grouping of the injectors before the regulator.
It can take a while for that sludge to work it's way out of everywhere. Ive had the same trouble myself despite intensive cleaning.
Def initially caused by HG leaks though
turbo engines are pretty low compression so it makes f-all difference to smoothness, to me at least. On high compression NA engines, esp with a rwd, it can be a must on the track to avoid instability
How many valves? One or all of them?
If a valve isnt seated properly it can burn. Basically happens when the valve sees a flame front which it doesn't normally do without combustion occurring around the valve - antilag, launch control, leaking etc
E85 makes for a cooler charge temp but combustion temp can be just as hot.
There are a few different rack ratios around. 2.2, 2.5, 2.7 ...
Spec c's got the 2.2. Most STIs have a 2.5 and other cars have the 2.7.
All racks up to version 8 will bolt up to the subframe but the steering column spline changes to a finer spline for v7+. v9+ racks have a different mounting bracket.
Oil line connection positions vary wildly but a lot of the time you can make it work
I buy the motul PA90 oil for the rear diff that has the FM in it already
Correct dont use FM with DCCD, well you can but it doesnt need it and your synchos will wear very quickly
Dont use oil with friction modifier in your gearbox, it destroys synchros.
DCCD stuff is designed to work with normal gear oil and without FM
Plated rear lsds need FM. Torsen doesnt
I like motul in my rear diff, redline in my gearbox and elf in my engine lol