One of these for example.
http://aerocharger.com/66series.php
No oil supply or return needed.
No waste gate needed.
Very fast spool, and since the bearings are "forward" of the compressor wheel, v/s being in the middle/CHRA like most turbo's, this design runs cooler, and uses thinner oil, so along with the variable vanes, the thin oil allows for very fast spool up.
Full boost of say 6lbs at 1800rpm would be a nice addition to the S8 in every day use, and while it's not going to make monster power, it will make amazing tourqe, and plenty of top end power for this street car.
With the lack of a waste gate, just replace the stock muffler with this, the other pipes to get the boosted air to the engine, and it's done in theory. (Now just need to figure out the additional fuel...)
And come up with about 4k to make it happen.
