Ordered one of these from Harbor Freight the other day. Finally came in, and since the rx-8 was due for an oil change I decided to give it a shot. Real easy to use... stick one of the attachments down the dipstick tube, connect it to your compressor, and drink a beer.

Came back, changed the filter, and started adding oil. 3.7 quarts go in, it's still at the bottom of the dipstick. Add s'more, start the car, shut it off and check again. Ended up putting in almost 5 quarts of oil before reaching the fill line. A definite recommendation... much easier than a regular oil change, and does a better job.