dont worry about haze's post, lost case.
it can be done, if you buy a t5 borg warner box out of a series 2 vn or vp it will bolt directly on without a problem, if its a different series then you will need to buy a flexplat adaptor that bolts onto the the auto flywheel then onto the back of the motor. so you can buy a series 1 5spd box and put it into a series 2 motor, the adaptor can be purchased from marks4wd adaptors in melb for like $315.
The auto and manual Vr's have different ecu's and wiring harness'es under the bonnet so you will also need a vr manual ecu and wiring harness, get it from a wrecker for about $200 max (very hard to get thouhg).
the rest is simple, bolt it all together and bobs your uncle.
YOU WILLL GET 10LTR TO 100KM with the 5spd box normal driving and freeway about 8ltr per 100km, so you will save money at the pump, need any advice mate,,
hope this answers your question,, i know it because i have done it to my car! vr berlina v6 manual.