Also what make/specifications are the engines that cessnas and warriors use to make comparisons with the RX-8?
You'll find this sort of information in a copy of "Janes all the worlds aircraft", if it's worth it's salt, your University library should have plenty of back copies.
Aircraft in the front, engines in the back (if it's a seriously old copy, airships before aircraft), both in alphabetical order of nationality, then alphabetical order of manufacturer.
The "World directory of leisure aviation", which costs about £6 is worth getting hold of for a different slant on similar problems.
One hint with engine data - always check you are comparing like with like, different companies will use subtly different horsepower definitions (cross-check kW), and there's no standard as to what combination of ancilliaries are attached for the weight and dimenstions quoted.
G