I think it will be close with the advantage to him. The last version of the E55 (2003-2006) had 469hp and 516ftlbs of tourque with a curb weight of 3990lbs. That would be 8.5 lbs/hp. Estimating your car at 410hp and curb weight of 3479lbs, you would also be around 8.5 lbs/hp. The difference comes in tourque, his 516ftlbs as compared to your 400+ and the gearing which an unknown.
Sounds like fun though... good luck!
H
