not from hawaii, but spend a good amount of time there...as for the 240/drift scene, it's pretty much dead.
since the track was closed several years ago, drift session has no where to throw events, and a lot of the guys sold their cars...hypersports closed, dont think endless garage is in business anymore. as far as shops, the only two i know of that are still open (on oahu) are vakamon and munky works.
cops caught on to a lot of the street drifting, so not a whole lot of that going on anymore.
still not too hard to find a decent party, depending on what you're looking for...wednesday nites at Dave and Busters is decent for the "just turned 21 crowd", normally it's promoted by a local hip hop radio station-might wanna check that out.
other than that, mai tais (at ala moana mall) is always good, as is the yard house in waikiki.
Depeding on where you're staying, i can recommend other bars around the island, but more the small neighborhood bar type...
kip and the green-bottle guys normally have some pretty good parties...check them out
http://www.green-bottle.com