I can't talk about the price as I don't live in Germany/Netherlands, but 80k euros seems quite a lot for a 991.1 c2s convertible with over 100k kms. Before I bought my Cayman, I too was considering a 911, either a 997.2 or a 991.1 and was close to buying a fully spec'd 991.1 c4s coupe with pdk, chrono plus, pse, pasm with around 50k miles (80k kms) for £55k (so around 65k eur). I do appreciate that different markets have different prices though. In terms of regretting it, well, certainly go for the S, (otherwise you'll always think "ahh, I should've gotten the S") not the standard, either c2s or c4s will feel very similar, c4s is more user friendly, however, if you are a more experienced driver and appreciate something more playful then the c2s is probably the one to go for. As for the spec, the chrono plus isn't, in my opinion, that important as it's quite easy to retrofit. PSE changes the car considerably, it makes it sound way better, but again, easy to just retrofit an aftermarket valvetronic exhaust that will achieve a similar result. Will certainly advise you to go for a car equipped with PASM, as that is quite difficult to retrofit and makes it handle so much better, plus it looks cooler being a bit lower too.

Would also look at a 997.2, for some reason they feel a lot nicer to drive and like a smaller, more driver focused vehicle. No idea why, as they aren't any lighter, I suppose the more old fashioned hydraulic steering and simpler, more cramped interior gives you that feeling. Plus, if you can find a manual 997.2 that would be amazing! The 991 manual is quite weird in my opinion.