I've found a 1998 Boxster with about 55K miles on it.

According to the ads:
BEAUTIFUL PORSCHE BOXSTER ARCTIC SILVER METALIC WITH SPECIAL ORDER- RED FULL LEATHER POWER SEATS (A $3,890 OPTION) MUST SEE! THIS CAR IS LOADED WITH SPORT TOURING PACKAGE ($8,068 OPTION) TRACTION, LUMBAR SUPPORT, HI FI SOUND SYSTEM AND CD CHANGER WITH EXTRA SPEAKERS, CRUISE, WIND DEFLECTOR, ON BOARD COMPUTER, SUPPLE LEATHER IN REAR, POWER WINDOWS, POWER TOP, AND MUCH MORE. CARFAX CERTIFIED! THIS CAR COSTS $60,000 NEW AND NOW YOU SAVE$$ ONLY $13,998. A FRESH TRADE IN HURRY THIS ONE WONT LAST LONG.
Like new condition!
Super Low Miles

Assuming there was no accident before, is this a good buy? Is the car reliable? Will the car give me technical problems?
Let me know, thanks in advance!

 

Good price, but keep in mind you are buying a 12 year old car, so expect some repair bills. Parts and labor are going to be higher on a Porsche than on a Honda. If the car suffers a slipped cylinder lining or a IMS failure, can you afford 12-15k to fix the car, or would you be fine taking a hit and moving on to the next car? The instances of catastrophic failure are low, but you are rolling the dice IMHO. The early cars also had convertible top failures which required updating the top transmissions and cables to the newer style. Typically, boxsters require gas and oil, and you just drive them, but there can be occasions of major repairs being required.

At 55k, I would expect the car is going to be in need of brake pads and rotors. Having a shop do it will run you around $1000. Also, 60k miles is a major service. Book time is 12.9 hours on that job.