HI Craig,
I just bought & am in the process of getting my Holinger gearbox.
It is 18,000 AUD btw + shipping to you (probably about 500-600 AUD) from what I have heard from other users, the noise is not too much and the driving can be smooth (after all as PEGLEG pointed out, you still have a clutch pedal).
You can order the tranny from them directly. Basically companies like Tomei, JUN and others just buy a Holinger with their own custom gear specs, and then resell the thing to you...
The gear ratios for the other companies are no secrets either, and basically you can ask Holinger to make your transmission to the specs of your choice. I have made a list of the various ratios that the "ready made" companies offer, so if you are interested, I will type them out and post them up here for everyone to see...
For fitting the current Holinger GT-R gearbox to the R34 you will require, an R32/R33 transfer case, a mounting bracket (Tomei sells that), and an R32 style clutch. I am not sure about your rear differential, but it *may* need changing depending on the final drive ratio you need.
Oh, and one more thing, you also have an option to have the clutch splines uprated on the Holinger. This means that Nissan clutches will not fit, however, with the new size you should still have plenty of options such as Titlon, HKS, etc.. I believe that the uprated clutch splines they use are the same as those used by Chevys (and we know that there's plenty of Chevy parts available in the US
