The BMW M5 E60 is all about that engine, the high revving naturally aspirated Formula One derived engine is a perfect compliment to the finely balance chassis laced cutting edge technology.
Pistonheads Forum Buyers Guide – incredibly detailed buyers guide written by an owner of a M5.
Eisenmann – M5 aftermarket exhaust specialist.
M5 Forum – Knowledgable owners who will answer questions you have about the M5. The forum also features lots of technical guides.
Fifth Gear review of the M5