We are doing this swap into a BMW for Lemons. It can be done on a budget and may in fact turn out to be a great swap, it is on paper anyway.
Key is the trans. VQs do not bolt to older VG trans and there are no adapters that are made to do so. The auto box VQs have a removable bellhousing that may be adapted to something but it is not known what it may bolt to and what bits may be needed to make it work. As such the VQ 350 or truck trans is the easy way to go. They fetch around 700-800 if you want one fast but can be had for a good bit less if you are willing to wait and turn over some rocks or rebuild a broken one (early ones had synchro issues).
If you go the 350 trans route you will also need a starter from a RWD car and may in fact need the RWD oil pan with pump and 350 exhaust manifolds or headers may be nice adds as well as the VQ30 exhaust manifolds were known to be crap.
The VQ30 has a few significant upsides that led me to wanting one for our Lemons build. They are dead cheap and everywhere. The maxima chassis they are in is pretty well crap and will rust away to nothing while the motors last for very long times. A crafty person could buy a wrecked or rusted or no title Maxima, pull the motor and sell off a few bits and scrap the rest and in effect have a free motor, this is what we have done and its not hard.
Best of all, the VQ30 in stock form with decent exhaust should make around 200hp if its not beat all to heck. It will rev, have a nice broad curve and be somewhat easy on fuel while only weighing about 350lbs in a very small easy to package wrapper.
As for getting it to fit in a E30 or about any else, not hard at all. It is shorter than a BMW 6 in height and length and is really not much wider. Add to this that the weight of this motor is LESS than the iron block BMW 6 while sitting farther back in the chassis... whats not to love?