I just read some of the posts I didn't really look at earlier and noticed that it's your Dad's car you're talking about. You came to the wrong place to have someone convince you a Boxster is too much trouble and you should go for the Japanese pacticality
Here's the deal: as an owner of what would be considered a pretty atttractive MY 2000 base with 50k miles on it I'll tell you that if I were selling my car I'd expect around $18k and that's an informed estimate because I thought about that recently in determining if I'm keeping it for the long haul and need to plan for a 3-car future. If I were looking to spend $20-25k all in for another Boxster in my garage I'd be looking for a 2003-2005 base with 30k or less for mileage. Forget the warranty and spend the $4k on a car that's a couple years newer with fewer miles on it. If you're putting 5k/yr on your commuter what's the Boxster going to get? 5k? 8k? You'll have a warrantly to protect it in your garage for 36 months / 20,000 miles at that rate. Get a '04 with 30k miles and it's not going to break down in the next 20k miles. You'll still have to pay for the brake jobs, expensive tires, etc. either way. Warranties don't cover that. You'll find one before long if you keep your eye out and have the cash available.
My car is hitting some maintenance bills now simply because rubber seals and belts only last so many years. On a 8-9 year old car things like water pumps, engine mounts, cam cover seals, etc. start needing replacement. buy a newer car and delay that hit. I'd say either steal Dad's car and forego the warranty but get used to the idea that some of the money you saved is already "spent" for maintenance, or research the market for a few months and see how new a car you can get with low mileage for $20k so you don't need a warranty.