far out there are a lot of bitches on here!!
i ran my M35 (yes different car, but same principal) without a front drive shaft for about 3 months.
it 'felt' lighter, and was a little more deliberate coming into corners, less understeer. and best of all, it was a little better on fuel!
there is always drivetrain power cost, so removing the front drive would probably make your car a little faster, but without the AWD grip - as already mentioned.
its a 10 min job to remove the front shaft, just do it. if you dont like it, put it back. simple