it's easy and cheap to add heated grips to the '08 bike (EC heated grips are < $65). By design, the heated seat will really only work in pretty cool temps. There are companies that offer after market seats with heating. Neither are necessary for FL weather. If you're planning to do a lot of touring up north then grips might be nice, but don't need to spend $1500 to get them.
The '09 tire pressure monitoring system is a valuable addition, but I haven't yet heard how well it functions. Nevertheless, here too there are after market options.
Bottom line, it's not like ABS or airbag. All the features of the comfort package can be relatively cheaply added if they're really needed. I certainly wouldn't pay that kind of money for them.
Fred's gotta a good point about your climate. I'm here in northern VA and it can get a bit chilly during the winter.
When I picked up my '09 Wing last October, the temp was 50F that evening. About 10 minutes down the road, my butt started to get warm and when I looked down, the heated seat was on setting '3'. I hadn't realized until then that it was on. It felt very nice and helped keep the chill off especially going over Mount Weather. And that is with me wearing jeans and my Olympia airglide pants (with the liners installed).
I can't speak to its "worth" to you. My wife and I thoroughly enjoy having the heated seats and grips even with our heated gear on. I don't even need the grips until it gets in the 40s. But since I have them and the seat, I use them all the time in the winter and will in the cool spring and fall mornings. They do make things more comfortable and pleasant but then again, I'm a bit further north than you.
I'm unaware of any cheap or easy aftermarket heated seat options for the GL1800 like there are grips.
An additional thought on the TPMS.
I had the TPMS come on for me once. The temps had dropped quite a bit from the previous day when I had aired up the tires. When I started rolling, the TPMS light started flashing. When I checked the pressure it was about 32psi. I aired the tires back up and the TPMS light stayed off. Pretty cool. I think that's also a nice feature but again as to its worth to you, well, that's your call. :doorag:
You can't really go wrong with either and Hal has some amazing prices on the '08s.:yes1: And I'm a bit suprised the difference is only $1500. I bet you could do MUCH better on an '08 than that.