second gear question(s)
 

I was looking at a 2000 boxster s today, and when taking it for a test drive, I found the transmission did not always, about 50% of the time, engage into second gear. it could be forced into gear by holding the shifter back to the stop and releasing the clutch. the problem was most noticeable during the upshifts and not so much during downshifts. all of the other gears appeared to work properly, the problems were only in second. does anyone have any ideas? is this a cable adjustment issue, a synchronizer, or perhaps the gear cluster?

Sounds like a Syncro issue, but I could be wrong.

Sounds like it's transmission rebuild time.
I'd walk away unless you can negotiate a proportionate reduction from the asking price...

a cold 6-speed will do it a bit until it warms up (one or two passes through second) and there is a fix (search the gbox website for the detent fix). if the issue is pronounced and ongoing even when warm then xmission is ded (cheaper to replace then rebuild).

The Radium King is correct but if it is not caught at the early stages it will likely only get worse resulting in a transmission rebuild (~$3k) and other "while you're in there" costs; Clutch Kit, possible Dual Mass Flywheel, Rear Main Seal and obviously an IMS Bearing upgrade.

I went through this several years back, it all started with what you've described in your post. If you have not purchased the car already or are on the fence figure in $4k minimum if the transmission needs addressing which in the Porsche 6 speed boxes is not unusual, the 996 Series 911 / Carrera's have been known to have the same issues since they use pretty much the same unit. My write-up on what I did:

IMS, RMS, Tranny R & R Tips - 986 Series (Boxster, Boxster S) - RennTech.org Forums

Ditto on Coreseller and TRK. Mine was done at 142k. $4.5k to rebuild w/ Guard torque-biasing diff and Gbox pop-out fix, I pulled the trans and took it in. Shifting has been perfect for the last 28k, but it didn't come cheap.