Definitely avoid the sun roof option, 60lbs added to the roof will NOT improve handling
Don't bother with leather upholstery as it is very slippery, the cloth has much more grip to keep you in your seat.
The MINI 17" wheels are monsterously heavy and should be avoided, if you want 17" wheels, shop around and find the lightest you can afford. Centerline makes a very nice 17x7" wheel that is only 13.5lbs, compared to 22 or 23lbs for the factory wheels.
The HK stereo and 6-disc changer would be a waste, or any other aftermarket stereo for that matter.
Basically anything that adds weight without adding preformance should be avoided
The MCS comes with Sports Suspension + as a standard, thats about as good as it gets. If you go aftermarket and add lowering springs you will be put into a higher class, not what you want. Aftermarket shocks would be a good idea in the future.