Got a P&L catted header, titanium coated inside and out. Also bought their overpipe. This, mated to an HKS FP + Ti Hi-power Spec-L CBE.
Impressions...
These are very solid pieces. Ain't no flimsy bits here. Approximately the same weight as the stock header w/ shielding. No weight savings. Lol.
Extra bung already present for a wideband. Header clearance with everything with the loop in the front is fine.
OP clearance was another thing though, had a clearance w/ frame problem, as I've read others have with some larger overpipes in general. Much too close to the frame, would've rubbed in turns, especially the way I drive in the twisties. Also, aside from from the frame issue, it didn't reach my HKS FP.
I could've cut up the stock OP, but I'm keeping my stock bits in case I ever wanna go back to stock for some reason (i.e.: if the ol' ball and chain complains too much of a too loud exhaust. Lol). Shipping is a bitch down here so I wasn't gonna deal with shipping back and forth another OP. Plus the time issue, I don't have a lot of it anymore like I did when I was a kid. So I just told the exhaust shop I go to to make it fit. OP was cut and extended in one section, mating to the HKS FP fine now and no clearance issues anymore.
Regarding the sound, tune, and drivability...
Stage 1 tune with the P&L header/OP plus HKS FP/CBE droned pretty bad at 2.5-3.5k rpms. Similar to when I just had the HKS CBE (before the addition of the FP which quieted it down pre-tune). Stage 1 tune with just the FP/CBE also droned bad but this was worse. Freeway speed at 60mph droned too much for me. At 70, not bad but my side of the island doesn't go over 60mph unless you wanna get tagged. Basically, stage 1 OFT tune drones too much for my driving with this combo for me.
Stage 2 EL tune, much better regarding the drone. Uphill drone at the drone rpms is still louder/irritating than just the HKS CBE/FP without tune but semi-tolerable, for now. Drone on flat ground is fine/tolerable. Not much drone at 60mph. No sound analysis or db readings regarding in-cabin drone this time as I just don't have the time for that stuff nowadays. Grownup life lately is taking priority. Sound through a tunnel... puuuure awesome! Love to roll down my windows, downshift, and rev it out in a tunnel nowadays. Just sounds amazing.
On the twisties I notice I'm faster. Accel is faster as higher speeds are attained quicker though various parts of the course. I have not tried the headers with the stock tune.
When driving like a granny, the car is now actually a little quieter (in-cabin, windows up) around town than with just the FP/CBE was. Also, sloooow low rpm driving like gently parking is quiet enough (windows down) I don't even worry about waking the neighbors. Driving around town the way I like to drive, you definitely know there's an exhaust on the car (windows down). I started rolling down my windows more just to hear the outside sound of the exhaust better. Didn't realize how much noise, good noise, there was to this combo until doing so.
Cold starts...
Did the cold start mods with Ignition Timing Post Start at 0. Quieter than -4, but louder than the anemic sounding 0 with just the FP/CBE. Still sounds like I have some exhaust, just not pissing off the neighbors now.
TL;DR
Pros:
Nice quality feel to the headers,
Ceramic coated inside and out,
Catted, can swap the catted part to uncatted if wanted.
Quicker accel,
The sound when driving through tunnels is pure awesome.
Cons:
Heavy, no weight savings,
Drones bad depending on tune setup and sensitivity to drone,
OP way too close to my frame, possible rubbing issues, needed modification