Has anyone here had a fiberglass tub or shower unit resurfaced, to either repair chips or other forms of surface damage, or to change the color? I've seen the advertisements about this, and seen displays at the mall, etc, but would like to hear personal reviews from the perspective of years down the road after such a fix. (Our house was built in the mid seventies, and our main bath room has fixtures in some awful 'trendy' color of that era. My wife wants to rip out the one-piece tub-shower unit and install a new white modular one. I'm wondering about changing the color on the existing one, since it is probably much thicker fiberglass than anything on the market now.)