i have a 95 jdm gsr tranny with oem lsd, i drive a lot of freeway miles and am looking at lowering my freeway rpm's, currently at 80mph i am at 4K rpm, i just read a posst on swapping an ls 5th gear in a b16 tranny but what 5th gear will work in my tranny

 

You can equip your GS-R tranny with the LS's 5th gearing. You just have to buy and install both, the LS mainshaft and countershaft 5th, gears.