Please Help!! I have a few questions about a 996 Turbo that I test drove today

I looked at (very carefully) and test drove a 996 Turbo with Tiptronic auto that was for sale today. It looked very nice except that there were a few issues that I have questions about. I've owned a 944 in the past and a 986S, but have no experience with 911 Turbos.
I would really appreciate it if you guys can quickly give some advice. I'm looking to do a PPI on it Tuesday and would like to know in advance if these "issues" are substantial or not.
I will list everything that I found. Please comment on if you feel that these issues are normal, expected quirks, or a common problem I should worry about.

1. drivers seat bottom appears to have seat foam bunched up in a small area in the front.

2. Slight hydraulic fluid seepage/stain on the bottom of the drivers side wing strut (visible on the left side of engine lid with engine cover open.

3. after running car with A/C (blows cold) for a while, there is a humming/whistle noise behind the dashboard area after the car is shut down. It lasts for a few seconds.

4. rattle from rear area of car only when cold. After it is run a while, no noise is heard. It sounds like a possible exhaust issue like a heat shield or something.

5. Car/throttle feels sluggish off the line unless I'm beating on the car. When driving normally, it sort of feels like the car is being held back. It feels like it's 200hp +/-. If the accelerator is fully depressed, it takes off like a raped ape!

6. The steering felt a little heavy compared to my older Porsches and my 2001 Boxster S, and it felt a little vague. I am wondering if this is possibly caused by the stock wheels that were exchanged for the Turbo wheels off of the 2007's.They also added 5mm spacers on all wheels to avoid rubbing issues. Is it possible that the new tires/wheels, that are slightly bigger in diameter and have 5mm spacers are causing this feeling, or am I just spoiled with incredible Ferrari steering?

Thanks for any help!

 

Thanks for the info guys. I really appreciate the help. The main reason I'm drawn to this car is that it only has 16,000 miles! I feel like as long as the PPI comes back clean (no issues other than the ones I found) and the rattle noise isn't something serious, then I should go for it. It's a 2 owner car with full service records. The paint and interior is in excellent near showroom condition! It has the exact color combo that I wanted and the 997 wheels look sharp, as does the aluminum trim pieces (still has originals too)!
Here she is:
http://www.ebay.com/itm/2001-PORSCHE-911-TURBO-16K-ORIG-MI-TIPTRONIC-AUTOMATIC-TRANS-SHOWROOM-CONDITION-/331258490047?nma=true&si=Apt%252FWfedSMOVm0FY6BChFDuL4aI%253D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557

 

I decided to pass on it for now. the main reason being that it had the 997 wheels. I love the way they look, but after thinking about it, I am probably asking for differential problems with them. The stock wheels are VERY close to the same diameter front to rear. The 997 wheels are almost 1" different!
I thought it was ok since the newer Porsches had that size difference, but then realized that the new differentials are computer controlled to compensate for that, the 996 is a fluid based system. The result is the same as if the car is being beat on and the tires are spinning all the time as it's being driven. If my numbers are accurate, the stock tire/rim set up varies by 3 revolutions per mile and the 997 wheels vary by 23 revolutions per mile!! I think the magic number is to be within 6 +/- revolutions per mile on these cars. I feel like the price was not low enough to compensate for the hassle, cost and possible future risk so I'm passing on it.
Thanks for everyone's advice! I truly appreciate it. The search continues!

 

Yes, that's what I tried to explain. I tried to explain that the tires were almost 1" different front to rear. I assume that it wasn't enough for an error light, but I wasn't comfortable risking the purchase.