I have a white lightning and have used the model 30. The 30 is very loud. The 2hp has an actual muffler the 30 just has a baffle. Just look at it when your at the store. If you've ever been ice fishing and you hear a very annoying and loud auger that sounds like someone took the muffler off, thats a 30.
In case you are wondering I have a 10" auger on the end of my WL and it cuts fine with the 2hp. A 10" is not nearly as fast as a 8" but I like the larger hole size for slab crappies.
I think I am going to buy a set of Stealth STX blades and modify mine.