Well you're probably right about the buying and selling. Spring is definately the best time to sell, although it won't be as good in CA since you can ride all year. Fall would be a good time to buy if you want new, but your selection may be limited. I'd say mid summer would be better. Spring rush will be over, and there'll still be a good selection of bikes. You may not get quite as good of a deal as in Fall, but it'll be better than what you'd get in spring, you'll still be able to get the bike you want, and you'll still have half the riding season left .. ;D
If you go used, I'd start lookin as soon as spring is over. The used market (at least around here) is almost non-existant up here after september.
Ther are two foggys on ebay right now. Buy one and sell your bike. Now is the best time to sell. My guess would be that neither one will even fetch the reserve. Email the seller after the auction and find out what he would take for it.
RottenDuc: About the Hayabusa: I've been there and done that. The last bike I owned, last year, before my 02 S4, was a 2002 Hayabusa. Whilte it was certainly fast, it never excited me nearly as much as the "slower" S4.
The Hayabusa always felt ponderous, and was also a bear to move around my garage or a parking lot. The S4 is like a roller skate on wheels!
Having now owned the Ducati, I doubt I'd ever be interested in a Japanese bike again, unless they REALLY change the way they design their bikes.
You might also check our very own DML Classified section..... I happen to be offering my Foggy for $10000. Buying a second house so the Foggy must go, don't have to sell just trying to free up some emergency cash.
I listed my bike below both the bikes on Ebay, they want you to start at $10k and $11k. You can get mine for $10k now, no bidding. I also listed it $3000 less than the Foggy on Cycletrader.com and lower than the other regular S4's listed.
Anyone who knows these bikes would agree this is a GREAT deal.
Good Luck whatever you find.