I've got some ground effects of 91 z28 and i've got a few questions for you guys

I've heard fiberglass is hard/dangerous to sand, so would it be better to take it to a shop to have them painted? And one of the ground effects is cracked, i searched the message board and someone said bondo would work? Is this true? Thanks.

 

Fiberglass is not dangerous as long as you are not sanding/grinding in a non ventilated, unprotected (you without facemask). Is it hard? If you can sand bondo or any kind of body filler you should be able to sand/grind the fiberglass with a double action grinder/sander. Should you leave it to professionals?
That depends, how expierienced are you with body work. Again if you can do bondo you should be able to do fiberglass( i.e. kitty hair, one type ). On the cracked ground effect:
If you try to fix it with bondo, it will work, but eventually you will have to fix it again. Bondo/body filler will crack. Bondo does not flex and you will eventually "tap" something with the ground effects. I know someone who had a sport bike, Honda CBR600, I believe, and he did a pretty nasty wipe out on it. Well anyone who knows anything about sport bikes knows this, their bodies have alot of body plastic. He had the cracked panels "plastic welded" he sanded them back down and painted them, then good as new. Hope this has been of some help.
Rudy