Teck-9, I'm sorry to say this but I think you're looking at this all wrong. Clearly the Crossfire isn't the car for you and I'm sorry that you bought this car without doing your homework first.

Instead of fantasizing about how to make it faster by adding power or reducing weight and what car(s) would go faster around the track, why don't you take your car to a track for a HPDE session and learn how to use it as is? Maybe it won't feel as slow as you think it is when you learn how to actually use the car. Maybe you'll enjoy the XF more. Maybe you'll learn a few things about the car and start posting relevant information.

Or... Sell the Crossfire and buy a Z4 M Coupe (yet another German 2 seat, fastback coupe... ) and start posting on BMW forums instead.