I raced my buddy's modded AMG SL55 from 20 to 150 MPH and the cars were dead even. He got an initial 1 car lead, since he jumped out first, but the M5 stayed on his tail until 150 when we both agreed to let off.
He states his SL55 makes 600 hp and 650 lb ft of torque (crank figures). He has a supercharger pulley kit, ECU flash, short tube headers, high flow air filters, resonators deleted and higher capacity intercooler and I/C pump.
The only mods my M5 has are BMC filters, charcoals filters removed, scoops and Evosport pulley. My exhaust is all stock.
I seriously was expecting to pull on him at higher speeds, since I have read how the M5/M6 should beat the AMG's due to our 7-speed gearbox at higher speeds but then again look how much hp and torque his beast makes.
Do you think my M5 is running optimally considering I could not pull by him up to 150?
Do you believe he had 600 hp? Ask the guys at MBworld if these mods would yield 600 hp.