I did this install myself. Absolutely do not try to cut it while it’s on the car. You’re afraid of scratching the paint or warping the strip while removing it but the strip is much thicker and harder to cut than I really thought. You’d definitely damage the car way worse trying to cut it more than the strip getting damaged or removal. I guarantee that. The strip may get slightly warped if you don’t have a very good saw. Also read below for tips to avoid warping.
A couple of tips that I learned after one side that made the passenger side easier.
When pulling off the strip it’s not that bad. Pull side to side (door to door) rather than front to back. This will prevent the strip from getting a bend when you pull it out. It will pop out. Clips don’t need to be kept so don’t worry about breaking them.
when cutting I don’t have a real work bench so I had used a 2x4 on the ground to lay the trim on and step on the trim and used a reciprocating saw to cut and it was still tough to cut. The metal was thicker than expected. Maybe it was my saw. my big tip here is to only clamp/step on the parts of the stripthat will be discarded. I drew XXX on those parts of the strip. If you flip the strip around to make your cuts you’ll always forcefully step or hold down discarded areas. These parts get damaged but won’t be needed. My very first cut I made the mistake of holding down a side that was to be kept and it dented it slightly. I didn’t make this mistake again.
The cuts don’t need to be smooth. They’re going to get hidden. Seriously don’t worry about the ends too much. You can bend them out if they get squeezed when sawing.
overall I’m happy I did it myself. Saved a chunk of money and it was pretty easy. The sawing took the longest time. Put tape on the car as directed. Don’t forget to remove tape from the before putting on the bar to bolt down.
good luck.