Im kinda confused about the SOHC right now.

I made 250 torque, 225 HP on the stock maf, 550cc injs, RB25 Turbine, Log manifold, stock FPR, stock cams, head etc. 9:5:1 CR pistons from a DE (Wiseco) and around 89.5 mm bore.

So ive been researching, finally decided to get a HE341 holset and modify my log mani to a top mount.

But ive been reading about mec lifters, aftermarket cams, intake restriction, etc.

I was planning to get 300-330 hp with the new turbo, but after reading some posts of how hard it is to reach that with the stock head etc, im wondering what to do...

How much HP can be managed going basic on the engine? just port polish, a big turbo, rods (which im lacking) and a good tune with a new bigger maf? without getting cams, lifters etc since thats pretty expensive stuff :O

I think the limiting factor you have with the stock head is the camshaft. Try as you might, you can only get so much air past the valves. You need to get them to open up bigger and quicker. That should get you a lot better flow even without porting the head. If you're going to have the head ported, might as well install oversized valves. Mechanical lifters won't gain you anything but free range on cam choices without needing to mil the cam towers. There's a GREAT topic on ka-t.org about the KA24E-T head modifications one of their members did that I think you should look at. I see you're also a member there too. It's a sticky'd topic at the top of the SOHC page.