I think the wheels you're referring to are Carrera Classics, which are available in 19" replicas from Wheel Dynamics. Personally, had I not just purchased wheels for my car last year, I would buy a set in a heartbeat. If you call Carlos at Wheel Dynamics, or send him an email, he'll answer all of your fitment questions. He only does Porsches and he's very knowledgeable about what fits, etc.
As to the issue of 19s on a MY 97-98, I read quite a bit before making the decision to go with 19s. Porsche did make improvements to strengthen the rear suspension on the later cars, but I satisfied myself that I am safe driving the car on 19" wheels. The only time the rear suspension issue should surface would be if you drove the piss out of the car on the track. I don't plan to do so. There's a lengthy discussion of the issue on Rennlist. You may want to check it out. You'll have to decide for yourself how you plan to use the car. I've been driving mine on 19s for a year with no ill effects.
The bearing/bushing argument may hold water, but as I see it, they're maintenance items anyway, and inexpensive ones at that. Certainly, a few dollars for bearings wouldn't dissuade me from running the wheels and tires I want.
As for the look of 19s vs 18s vs 17s, it's a matter of personal choice. I like the look of the 19s. I think it's more contemporary and helps to update the older cars. I'll throw a picture of mine at the end of the post. You'll have to decide for yourself if it looks like too much rim or not. Personally, I think the look is even better if the car is lowered a bit, which mine is not. I can't get a permission slip from the missus.
I should also mention that I stepped up from 18s to 19s and didn't notice a decrease in ride quality at all. I've read that the car handles best on 18s, and that the handling starts to degrade on 19s, but I haven't experienced that either. I pushed the car very hard just last weekend, and it handled flawlessly.
Good luck in your choice.
