I agree most with Wagonbacker, using dirty dingo mounts should allow you to place the engine where the factory transmission placement belongs requiring no driveshaft mods. When you start messing with the drive shaft you can miscalculate the pinion angle or the correct amount of length needed. A couple of inches too short or long can result in either the drive shaft falling off or bending in an instance of great suspension travel also damaging the trans. I have seen this more often in the four wheeling world but never in everyday use if you do not tow on a regular basis. The dirty dingo mounts as mentioned above allow a total of 3" of travel, 1 and 1/2 foward and backwards. This should make factory line up as you started with. If it doesn't, just post what you have and go from there. Drilling new holes is no big deal, just as long as you are not moving far from what you started and wanting to keep your factory drive shaft.