AS FAR AS TRANNY GOES there are no part upgrade for OEM..u might want to check out www.v6performance.net. look on the left hand side of the main page and look for "ATTENTION ALL V6P OWNERS".
It will take u to the V6P TRANNY FORUM. Some shop is gonna put out a beefy tranny for the AccordV6 this year... at least we all hope. that is the best i can tell u on that part.

INJEN is good, plus u will have the option of going SRI or CAI if u buy the SRI.
lost low end w/ SRI but mid to top end is great. mufflers/catback will really help
mid and top end too.

Cams and stuff, sorry havent got into internals yet..still under warranty.

UR pullies are good they are mostly lightweight and slightly underdrive, no problems w/ alternator charge. Supposidly RVM is working on pullies also, but this is sketchy from what i have read at V6Performance.net
AEM pullies may have the alternator problem, i read that users may have trouble with too much underdrive and it drains alternator, especially if u have a sound system.

i read that some owners w/ OBX headers have a funny drone/rumble at certain rpms'..makes sense with a 700$ price difference.

I personnaly have MAGNAFLOW setup w/o pre-muffler and w/ resonator...not loud or ricey, nice deep tone. Greddy MX is a little louder, but deep. Comptech is not to loud and deep somewhat. of course it all depends if u run pre-muffler and resonator. There are some sound clips on V6Performance.net

Supercharger..you will need to really beef up your internals. $$$ but Tranny wont last.
NOS..wet or dry..tranny problems are likely. Stock engine can take about a 50 shot..tranny may last but????

just my 0.02 cents worth