Hey, no problem about 'late' response.. we all have lives outside of the Forum, no?? I mean, I am constantly online here, but that does not mean i sit 24/7 infront of the computer waiting to reply to threads..
"Green behind the ears' is good. You are willing to learn, and are asking intelligent questions, so no worries what-so-ever..
You get an "atta-boy" from me..!!
Ok, the Injen, in and of itself will not require a "tune".. You would "only" be allowing the airflow BEFORE your throttle to become better (Less turbulent), and louder (unresonated/sound deadend). If you do not change anything on your Throttle and/or Intake Manifold, the amount of air being sucked/drawn into the engine will not change.. The Throttle hems/controls this. You have an 08 so this means you already have a larger Throttle (64mm) than the 03-05's (62mm). Too, your Headers "runners" (Tubes/Pipes), your Cat and Intake Cam is better than the pre-facelift. What the FP can do for you is help reduce/banish the 'lag' caused by DBW, and you can lower or raise your v-tec engagement points. You can also raise your rev-limiter, but be careful here!! The TSX Oil Pump is only "good" to about 7500-7800 rpms.. thereafter it 'could' cavitate on you, not delivering enough/any oil pressure, which could be utterly fatal. I would not change anything on fuel trims just yet.
If you want more info on Intakes, Goforbroke (I believe that was the members Nick) and I had just recently had a chat about this,, It was maybe 3 weeks ago, so it should be easy to find.
There also a few other things you can change, in the mean-time, that will help your car accelerate somewhat better, no tuning required. Lightweight pullies are an option (Though there are different 'feelings' towards installing an non-harmonic pulley on the Crank, like the oem has...) and also your clutch/flywheel can be 'lightened'.. cost's a bit, and i cannot say what the single gains on this Mod is, because i drive an A/T.. Flywheel, ok, but clutch i have not, well not in that sense.. nothing to be done here (on A/T), except maybe 'gearing'..
So young man, I believe i have given you a few things to chew over.. If you have more questions feel free to ask. Most members here are more than willing to help, where possible..
Greetings
ACC-Man
P.S. say "HI' to my Mom in Midland, and My sister, in Mississuaga, for me would you..??