[woodsman]

I think tramlining is dependent on the tire itself- ie the strength of the corner where the sidewall and the contact patch meet.
Regarding rim widths what it comes down to is support of the tire. Where you are in the approved rim width range effects the shape of the contact patch which effects how the tire performs and communicates. If you never get to the limits of adhesion this matters less but an oversize tire will tend to feel numb- like wearing oversized winter mitts. The car will also feel heavier.
Then there's scrub radius. That's the arc the wheel passes through as you rotate the steering. Offset effects this and can change how the car steers. I ran a 17mm spacer on the front of my car with stock 18*7.5*50 and the steering was abrupt and too sharp- it looked perfect but it wasn't worth the loss of precision to me.
Just saying there's a lot to consider when we stray from how Porsche set things up and we often discover unexpected consequences. But then that's how we learn isn't it? Play on ...