No, I like the sport techno wheels, bbs style are hard to clean. Yes 19" will' work' , but the ride will be rougher and they will send odd signals to your PSM system. I wouldn't mess with the handling/steering geometry that porsche has put in these cars to work together with a very sophisticated awd/psm system.
I'll tell you that I do notice the AWD correcting itself a bit more with these rims on my car, you feel the car shifting traction right to left/front to rear. When I put my summer rims back on, gone.

 

I actually found that out later myself. The stock C4S rims have a 45et rear, the sport technos use a 17mm spacer and have a et63 stock from the factory.

 

Are the sport techno wheels different enough from the stock turbo wheel to spend the dough? I haven't seen them in person.