968 oil, tires, and specs

[94ontario968]

Hello Porsche fans!
I've purchased a 968 in December'03 and I am getting ready for a second season of motoring (that's May to November in Canada).
As I've just joined this group today I thought that I give it a try with the following:
I have 3 general questions that I hoping to get some feedback on.
1. What grade of oil would you recommend to use in an 968? My car came from California where it was using 20W50. I am thinking that for the cooler Canadian climate, a 10W40 should be a good choice.
2. What brand of tires is the most favourite among the porsche users? I am looking for a good mix between performance and wear with as minimal noise as possible. Currently I have Michelin Pilot Sports and they seem to be a bit noisy for my taste (maybe because they need replacing) and they're not cheap either. What about Bridgestone Potenzas, Kuhmo Ecstas, or Continental Conti Sports? I was also wondering if I should even go with the A/S such as the Michelin Pilot Sport A/S.....
3. Where can I look up specification for my car? Perhaps there is website where I could input my seial number / VIN number and retrieve the exact specs of my 968. My car came with the optional 17" wheels and apparently the optional sport suspension as well...I'd like to find the details....
thanks