1. Your dealer will be able to put anything on your MINI configuration that you cang et on the website. The dealer will also be able to go into all of the dealer-installed options that might not show on miniusa.com
2. Depends on when it's going to be built. I think it currently ranges from 4-8 weeks depending on if you can catch the next build allotment.
3. As above, with the current lead-out for a new build, you're coming very close to the factory transitioning over to the 2006 model year cars, and no more Electric Blue. Act soon if you really will accept no other colour.
4.
DSC is a life-saver for when things go wrong on the road (it will work with the ABS to module braking on each wheel individually). You can live without it, but with north east US winters (I grew up in NJ) and the relatively poor condition of the roads there, it might be a good idea. You'll appreciate it if/when it saves your life. The Limited Slip Differential is an excellent performance
mod as it will limit the amount of wheel spin on one of the drive wheels. This will give you more drive coming out of hard/fast corners. Whether you need/want that or not is entirely up to you.
5. Since we're still in the transition period between 2005 and 2006 model years, I don't think you'll see a price increase (or much if any). Because the build time for a new order submitted now may slip into 2006 model year production, they'd have to give you the 2005 prices for the time being.
6. <shrug> more metal, more polish, more complex, limited production... take your pick. It's a seller's market.
I grew up and still have family in Essex county. What MINI dealership is near you in NJ?