[Perfectlap]

If you aren't a distressed seller as you put it then don't actively attempt to sell the car until tax return season. You are already in a buyers market with any water cooled Porsche, and going to a wholesale purchaser no less, is the absolute least amount of Market leverage you'll muster. This time of year the guys at 1800 probably only deal with distressed sellers or soon to be house hunters needing cold cash for a down payment.

If I were you I would aggressively look for the Turbo, and only low mileage Turbos as this is the best time to get the lowest price for low miles. Moderate to high mileage you can score at any time since most of those owners are always anxious to get out of those before the big wave of pricey repairs come in. Low mileage owners are in no rush and youll only have some leeway during winter. but check the forums first an enthusiast Owned Porsche is always the best Porsche to buy.

As far as not being able to ask too much for your well kept Boxster because you'll be into 996 territory, that's not true at all. If someone wants a well maintained Porsche roadster, a tin top Carrera isn't going to get them that driving experience. Even if they buy a 996 Cab the handling is completely different, its a bigger heavier car with much more under steer and if its a C4 Cab there's no fixing that under steer unless you sink some big money into the car.
996's are not expensive and examples at or below $10K will be common soon. We're talking about 3k water cooled Carreras listed daily on Autotrader. If 996s were difficult to find then you could make the argument that no one would pay good money for a Boxster that's been well cared for. But both 996 and 986 are easy to source. Don't let any salesman or low ball private buyer try to use the "I can buy a C2 for what you're asking for" argument. If a 996 is what they really want then they've got no reason to be looking at well cared for Boxsters as there are infinite numbers of motivated 996 sellers. Especially now that the 997.2 Carreras have begun to come off warranty and the large delta between 997.1 and 997.2 will start to come down, pushing down all non-GT 996's in the process. The thing working against you now are 9A1 987 Boxsters coming off warranty and into the used market.