Just wanted to let you guys know... the TSX reflash is by far one of the best mods you can possibly do. If you are curious in ANY way: JUST DO IT.
Beware however: Your car will be faster, meaner and pull harder than you were previously used to. Your girlfriend/spouse may not like that.
The biggest gain has to be between 3-6k rpm's. This is all useable for every day driving. When you step on your gas, you're going to feel the extra pull, no doubt about it. While Hondata is tuned for an Intake and Headers, you can certainly have the mod without. I have no aftermarket header, but am still enjoying the benefits of Hondata.
Bang for buck, Hondata is the BEST performance mod.
See my dyno:
Blue line: Hondata + Comptech Exhaust
Red line: Hondata + Injen CAI + Comptech Exhaust
Car: 2005 TSX 6MT - 1,980 miles