i feel i should weigh in here...
i swapped my E85 Z4 3.0i for an early 986 boxster S. the boxster had the better steering feel, and was very planted through the corners. flat 6 made a lovely sound as well with a sport exhaust on. interior of the 986 was seriously dated though - cracked grey leather, seats like sofas, which were set too high, steering wheel set too low for me, radio looked like it was from the 80s.
come the spring i'll be swapping the 986 for a 987 - considered if it would be enough of an upgrade to warrant the extra cost, but i figure, its better looking than the 986 (which had the infamous fried egg headlights), a fraction more power, but more importantly, better seats and interior, seats go lower, steering wheel adjusts for height, gearchange is tighter. its also on larger wheels, which can support larger tyres - so better for track work.
i think i'd get on well with an early cayman s, but 2006MY has the higher road tax, and the 3.4 is far more likely to suffer borescore than the 3.2. plus, it is nice to be able to drop the top on nice days. i'm very much looking forward to getting in a 987 S.