1. Yes and no. Many people have had issues due to SPL and many people have run it just fine. All depends on if you're a bass head or if you're more of a normal listening person.
2. Yes, it will absolutely matter. As with frabicating anything, the materials are of upmost importance. MDF is the usual material because it's cheap and easy to work with. Is it the best for this application? Hard to say when you don't know for sure what you want it to look like and how you want it to function yet.
If you're looking at building a center console you had better practice some fiberglassing and bondo work first.
Good luck with it all!