I spent a little time doing some porting on the head on the engine I built for my old turbo 2.3 and it was definitely worth it. A ported head + bob's log (or similar manifold) + whatever turbo you want + bob's 3" elbow make for AWESOME spool times. I just had stock valves but I got a valve job and polished the chambers. Also ran a motorsport A237, I know people say it's not the best for turbo cars but mine felt stronger with it than the ranger cam.
I was running a 57 trim hybrid with a .63 Stage III turbine, which I had heard people complain took forever to spool. With the above work it spooled like a stock T3.
I especially saw a big decrease in spool time just going from the factory exhaust elbow to Bob's 3" elbow, that helps a lot.
2005 Mustang GT
CMS Stage 1 cams, Lito Tune, C&L Racer, CMDP, SR UDP, JBA LT's & catted H, FRPP Touring AB, Koni STR.T, BMR springs, J&M upper/mount, BMR lowers & brackets, J&M pb, Steeda Tri-Ax, Brembos
2009 Ranger XL SCab-4.0, auto, 4WD