This is my story, and I'm sticking toit!
First, I didn't dyno my car after doing the top end P&P, before adding the headers and X pipe, etc, so I can lie like a rug about how great it was!
I went with Pete's proven model for the P&P;
lets just say a 36 mm ball rattles through the plenum primary side like a BB in a down spout! And, the IHs discharged into the heads which had "a little" over 36.5mm openings at the top, and tapered along the entire length to a point just short of the valve guide bosses (approx 32.5mm stock 90s).
I was expecting about 25-30 hp (with a Haibeck chip installed & fueling setup for an additional 50 hp). However, I was flat amazed!! - I'd have to say it was ALL of 30 and felt closer to 40ish! My shift point moved up at least 500 rpm, and it showed signs of things to come when it was very hard to make it stick in first gear on asphalt. In other words, I feel I gained torque in the low/mid range if anything - certainly lost nothing that I could feel.
Next step was to install the SW headers, the SW X pipe, and remove the resonator (leaving the muffs alone). Frankly, I was hoping for the same magnitude of increase in performance that I got with the top end P&P, but it was not to be. I would guess I got about 1/2 the increase in seat of the pants that I got with the top end porting. I was a little disappointed, frankly. However, that was when I discovered a leaking exhaust valve on #8, which no doubt played a role.
Well, the next
"holy cow!!!" had to wait until the head porting was done and Pete and Marc did their magic. Just one problem with it tho...I'm definitely needing some DRs, cuz the GY F1-D3s are no match for the RWTQ, and that is with stock 3.45 rear.
My recommendation is to go whole hog on the plenum and IHs and port match the heads for now. Then move onto the rest of it in phases as $$ allows.
Just a thought.
P.