It definitely changes the car from the tall geared OS 5 speed that I had in it. "Woke it up" as such.You don't need to run the OS clutches, but it takes out one less headache when putting it all together. I looked into trying to salvage the coppermix as they really are THE clutch to have in a road going GTR. (Mine was in there since 2005 with no service/rebuild at all). It was all too hard. For starters the coppermix was a pull type, this box only has the bosses for a push type, then there was the bigger input shaft issue. The R3C is awesome, much better than expected and NOT how I remember the R3C in other cars I've driven. The pickup/friction point is quite low compared to the Coppermix which takes a bit of time to get used to. Apparently this is the new type. What they have changed, I'm not sure.
You will need to supply your own transfer case.
There are 4 gear options available. I went option 2. Assuming a 265/35x18 tyre and spinning to 8000 rpm each gear will go to
82
118
160
200
234 (same as stock as its 1:1)
310 (same as a factory 5 speed as its 0.757)
You're basically slotting an extra gear in before the 4th gear in a factory 5 speed box. If that makes sense.
With the box, I bought;
Box itself
Modified cross member
Bent shifter
Clutch
Release bearing
Clutch aligning tool
There is a bit of crashing and banging at low rpm, but that's just me not getting the timing 100%. I've only driven 60 kms or so with it so still very much a noob. Up high and drive it like its stolen, smooth as silk. Just slides into the next gear, you don't feel anything through the shifter. As quickly as you can pull back on the gear stick its in. I've found preloading the stick before you lift seems to work well too. I'm still clutching in ATM but as time goes on I'm sure I'll be able to do the no clutch/ lift throttle technique. I'm obviously not tuning a strain gauge - yet. I wouldn't like to daily drive it but for a weekend car it's great!