So I just picked up an 06 H3 last weekend. Leveled the front and put some 315’s on it and gotta say I love it. It came with a k&n intake system from the previous owner. This did replace tire resonator box but not a big fan of the exposed filter. I just ordered a pcm of nc tune that should be here next week. Really hoping that it will help with shifting and pick up a little hp. I’m also I stlling a vette servo this weekend... so my question is would I gain anymore drivability with adding a ported throttle body and/or a header to the stock exhaust. I don’t want it to be loud and can even add a high flow cat behind the header. Main thing I’m looking for is torque as I don’t wind her over 5k.

 

My friend did a Header + catback exhaust and it was loud as the header removes the oem cat. The highflow cats dont reduce noise levels so adding one isnt going to be what you want.
You will also lose some torque down low so if your are not planning to use the full range of the rpm you wont make use of it. If you do plan to be hard on it though it will keep up with an Alpha.

A ported throttle body will improve throttle response and make it snappier but not much to hp gain. The oem throttle body flows well and the restriction to airflow is at the fender air inlet on a stock air box.

 

Yea that’s kinda how I see things. From what I read the headers are more of a top end increase and the throttle body will help it feel snappier but not really add anything.

 

Same mods as for all the I5s: Intake (Open systems are lame and I note your comment on the open filter ) PP TB, Efan Conversion, Cat back exhaust, and a PCM Tune to match.

With an I5 "Header" (there is only one) depending upon brand you may into CEL problems as your O2 sensors are looking for something different. You will likely have to play with and O2 adapter to change its position in the flow of exhaust. If you decide to go that route, use one that retains the front pup cat. I would have played with a MagnaFlow header on my 07 if the exhaust manifold ever cracked before I sold it. I know some others have had good results and little hassle with those.

Nice lookin 3.

 

That looks great! Care to share the specific wheel and tire sizes? And how the leveling was achieved?
I just bought same for my 16yr old and seek to go lower in rear instead of higher in front. It will be a city goer.