Not a good comparison at all, way too many variables. There's no way to tell if your car is mechanically up to par because of a lost race. Codes/scans/etc are the way to go in terms of that.
He's got quite a bit mods against your stock 335i
6MT so one driver could be better at shifting or vice versa. one driver could have just had a bad launch/roll
try racing without passengers/guessing the extra weight. any added weight considerably changes things
go to a strip and do a real test. but buy a tune first!