As I recently posted in the Installation forum, I recently had some blokes install my Mk2a in my 1999 Miata using RF. The result is obvious sound quality loss, engine noise interference (even though they installed suppressors), and a constant annoying background wave.

RF clearly is cheaper but I wouldn't recommend it unless you know that the shop would be willing to upgrade you to the more expensive configuration without charging you an arm and a leg.

Me, I'm looking forward to arguing with the shop that I dealt with as I believe that they're going to want to charge me for the labor of installing an amp -- when it was their not-so-brilliant idea to go with RF in the first place.