Need help deciding on two Boxsters

[ecwfan]

I have been looking to buy a used Boxster for a while. I have narrowed it down to two different cars. I need some help deciding which of these two to buy.

2001 Boxster S 6,000 miles Tiptronic Porsche Cert Silver $40,000
2001 Boxster S 11,000 miles 6 Speed Black $37,000

I am looking at the Tiptronic because I have never driven a manual transmission before. However, I would like to learn and understand that this is probably the best way to go if I buy a Boxster. I was wondering is if there's much of a diffrence between the Tiptronic and manual cars. I test drove a 2000 Boxster S Tiptronic and it seemed kind of sluggish. Would the 6 speed perform better in terms of acceleration? Since I'm a total rookie at driving a 6 speed I'm not sure I'll have a good feel for the car. I don't have much of a chance to practice beforehand as I need to act fast if I want to buy the 6 speed Boxster. Based on the above which car would you buy? Please note the prices on the two cars may be negotiable as I haven't gotten to the discussion on that part yet.
Thanks in advance for any opinions.