it's all about scaling your MPH. if you have a 10,000rpm redline, then your gears are pretty long. a 5.0x fd will scale things back down to "normal." there's a lot to consider, but on a high revving motor, shorter is generally better.
When my RSX was modded, my transmission had an ATS 5.062 FD, Quaife LSD, Toda Clutch/Flywheel. For reference, the ATS FD costs more because it is shot peened for added strength. The one JHP is selling is strictly OEM, straight from the box. I couldn't comment on the reliability.
The FD was a lot of fun in my RSX because the car was already heavy to begin with it. It definately helped with the acceleration woes. But when I swapped the tranny to the motor in my EG, I was in for a treat. I run slicks at the track so traction isn't a problem. I shift at 9k and I think the 5.062 FD greatly compliments the rpm range. Driving on the street is something to experience. I don't have traction in 1st gear but I feel that with drag radials, I will be able to solve most the issues. Ever hear a ricer civic that takes about 20 seconds to get through 4th gear and all you hear is the droning buzz of the exhaust note? Well watch my car, it's nasty how quick the acceleration is! It is absolutely euphoric :driving:
Yes, it would be really ridiculous mated up to a K24's tq and lower redline.