Greetings from Finland,
Me and my family made a road-trip from Central Finland to the German/Austrian Alps last summer - in a 964 Cab. Two and half weeks, approx. 6500 km of pure enjoyment. Weather was very hot at the end of July last year in Bavaria. It was very enjoyable trip we never forget.
Well, about Scandinavia. You just should ask what you are looking for. If nice twisty roads and beautiful scenery is your thing, then you should go to southern Norway. Denmark is quite much like Northern Germany, roads are very good but the landscape is flat. Big bridges (Oeresund / Stoere Baelt) are a must to see. Southwest part of Sweden is beautiful, if you drive through Denmark to reach Sweden In Maelmo or Helsingborg, you can start driving to the north via Gothenburg and soon you reach Norway. Never been there by myself, but some of my motorcycling friends have done it and they recommend it very much. Very nice twisty mountain roads all around.
One of my friend made the following (approx. 1000 km
Oslo - Kristiansand - Stavanger - Haugesund - Oslo. Check the road profile from Google Maps, mostly looks like a perfect road for Porsche - and always in good condition.
Central part of Sweden and Finland are quite much alike. Peaceful and quiet, lots of forest and lakes, quite flat but nice still landscape.
If you come to Finland, then you should go up to Lapland to see Nordkapp. I will join you to that trip with my 964. You cannot drive more north as the land just ends.
Best time to visit Scandinavia is in the middle of July, our summer is warm and most beautiful at that time.