Hey guys new to the forum, thanks for the add. I’ve found these ATS wheels and wondering if they will fit with 205/55/15 tyres.? The originals are 5.5x15 et40 and I’m not sure if the extra wheel width will make up for the smaller offset of 16? Tia

I’ve done some research on offsets and some calcs and I’ve come up with I need an extra 40mm clearance off the back of the wheel. Happy to be corrected by those that know about this…..The front of the wheel appears to sit in roughly the same position less 5mm as the stock steel.

Welcome- with a backset of only 16mm, compared to 40mm it is going to push your wheel into the fender almost an inch (24mm).

Standard Porsche 15x7 is 23.3mm offset, which sometimes fits the rear stock fenders depending on how skinny the tire is.
I'd say the ones you found would fit with flares but not as is and definitely not with 205/55.