Which Boxster you buy will depend largely on your budget. The range was constantly updated throughout the car's lifetime so the younger the car, the better the spec (and build quality). Early cars suffered from cracking in the cylinder bores while some engine's also suffered from the failure of the intermediate shaft bearing. But the most common weak spot of these cars is oil leaking past the rear main oil seal. This results in a drip and slow oil leakage but isn't terminal.