Hi Jens,
Bosica does'nt make a 911 but there's a ton kit's by other manufactures in 1/43rd. Check out kit's by Starter or Provence Moulage for a less complicated resin kit. AMR makes a few early 911's in white metal. Renaissance or Robustelli make resin kits with a ton of photo etch detail. Here's a couple of spots to look.
http://www.grandprixmodels.com/
http://www.amazing43.com/
joe