Hi mate, i work for Autoglass Some insurance companies will not pay for genuine subaru glass as it is more expensive than a patent part also most replacement windscreens are of a very good quality now. The trim should be changed when the new screen is fitted, looks nicer but may squeak for a day or two until the new screen has settled down. Your car shouldn,t go rusty just because a new trim hasn,t been fitted there would of been a scratch in the bodywork that had started to rust over a period of time. I,ve done loads of scoobs mate, WR1, RB320 etc. If you need any info pm me.