Stock Rim sizes / Lowering?

[Silveresrty911S]

I was wondering if you guys would know what my stock rim size might be for a "77" 911S. I'm thinking I might want to go to a larger size in the rear, 7-8"? Right now I have 205 60-15's all the way around. Also what is the cost for some used Fuch's and I would also sell my 15"x 6"or 7" ?

I'll post a picture of the car, I think I also need to lower it some. I've got "101 Porsche Projects" from Wayne and was wondering if ther is any other info I'd need before I start on this project. Thanks for any info you can provide.

Rick