GAP Insurance seems to be available principally through dealers and finance providers. I'll see if I can find out if you can buy it elsewhere - I'm sure that I've seen it sold through other outlets but can't remember where.
I know there are some other posts on this site about the cover when bought from the MINI dealership.
The "new car replacement" benefit means that the insurer pays for a new car (to the same spec) if your vehicle is damaged beyond a certain percentage of the list price. It's typically 50 or 60 percent of list. The usual rule is that the car must have been regd in your name from new and the benefit ceases after the car's 12 months old. If you take out another policy (with this benefit) when your car's 5 months old you'll still have the protection for the remaining 7 months or so. Imagine how gutted you'd be if the car was nicked or badly damaged at age 11 months and the insurer just offered you the depreciated market value?
The Chili pack thing is nothing to worry about. The insurer didn't ask you to tell them the precise option pack so they can't and won't use that to avoid liability. A Cooper Chili is still a Cooper - Chili is not a badged designation like Ford's Ghia tag. I think some people may have had problems because most of the people in insurers' and broker's offices aren't MINI enthusiasts and have no idea what a "Chili" pack is. They have probably assumed it's either a modification, or a different model that's not on their 'puter system.
Lastly, ASC+T won't make any difference but your alarm might knock a bit off your quote (likely to be a max of 5%).
By the way, I'm not part of any "mob" (no offence was taken)

- I've spent most of my working life beating down insurer's prices to get a better deal for clients and increasing the cost of their claims. Brokers, well some of them, act for their clients and are duty bound to put the client's interests above all other things.
Sorry to waffle on but it's all part of the training.
