I used Dynamat 11905 Hoodliner 32" x 54" x 3/4" Thick Self-Adhesive Sound Deadener (amazon.com) in my 99 RAV4 with excellent results. I used 3" aluminum insulation tape to tape up all the edges and a heat resistant spray adhesive to hold it in place. It keeps the hood much cooler and soaks up the sound.
It may be that my sole purpose in life is simply to serve as a warning to others.
RAV4.1, 1999 RAV4, 3S-FE engine, E250F transaxle 5sp AWD, 5 door, LHD, Redneck Edition (RNE), Mossy Oak Obsession wrap, heavily modded, TOAD
'96 Newmar Mountain Aire, 40' diesel pusher motorhome, the mothership