I'd want to know who owned the bike and why it's for sale with only 272 miles. Breakin is 600 miles no higher than 4000 rpms followed by oil & filter change and another 600 no higher than 6000 rpms, so it's never been broken in.
Many extended warranties are merely 3rd party insurance policies and fraught with problems getting paid, but Suzuki offers its own extended warranty, which should be fine. The full price on it is about $395 as I remember, so $500 either isn't a Suzuki warranty or its a screw job. You can buy the Suzuki warranty anytime while original warranty is in force. Details are in the Busa owners manual. Also, I don't think any Busas were delivered prior to late March 1999, so original warranty will run for 12 mos from delivery. If you're being told there's only two months left, something is fishy.
This dealer doesn't sound good, which means nothing but problems. Unless you can get some better answers, you might be better off waiting and buying from a different dealer. Is this a Suzuki dealer? If not, I'd for sure stay away.
But as for 2000 models being better than 1999, I doubt it. Officially there are no changes, except color, and Suzuki has been very forthcoming retrofitting existing bikes with fixes they've made in production.
Copper was the signature color for 1999 and it will always mark the inaugural year of the bike that has earned a guaranteed status in the history of motorcycles. That may not be true of the black model (which I own) because, according to my dealer, black was over-produced and will be available in 2000 in addition to the announced red and blue colors.