Forester XT engine rebuild
 

So, I'm rebuilding the engine in my new-to-me 2004 FXT. It's stock. Except for the VF39, STi TMIC, 3" catted TBE, and coated Grimmspeed uppipe. But since I'm pulling and tearing down the engine anyway, I'm considering a handful of other mods. I have some FHI non-TGV housings left over from the motor in the white RS when I bought it. I know there's peak power gains to be had from them, but will I lose any low-RPM throttle response or idle smoothness with them? It's just a DD, so I'm not really looking to sacrifice much in terms of smoothness for power. Besides, it's 4EAT so big power is out of the question anyway. Also considering an turbo inlet pipe- will one of these show improvement in spooling or boost threshold? If so, which one is the best buy? Lastly, does anybody know the differences between the EJ255 and 257 cams? I'm guessing the 255s are smaller and less aggressive, but would I even want to change them, with the 4EAT and not wanting to lose any more off-boost response than I already have? Lastly, I may also polish the intake ports on the head and maybe spring for a Grimmspeed coated/ported header and crosspipe, but that's probably low on the BFYB scale.

CN:
Have: VF39, STi TMIC, 3" turboback

Considering: TGV deletes, turbo inlet pipe, STi cams, coated/ported header.

I would do the TGVs since you have them and a cheap inlet pipe while it is torn town. Both are a pain to do later. I'd wait on the headers as they are fairly easy and pricey without a core.

Does it have the STI or Walbro fuel pump? Which injectors are on the FXT? With the VF39, I would be worried about fuel if it can breathe better.

Stock and stock. My understanding was that all the side feed injectors were pretty much the same.