I'm surprised that as often as I frequent this site that I missed this post. Anyway, I've owned 9 Monza's in the last 20 years so I know a little bit about them (still have my '78 Monza Spyder I've had for 18 of those years, thus the login name) Anyway, the Mirage was only made in 1977 and there were only around 4000 produced. Not all were V8's, but I would say 98% of them were, although I've seen two 4-bangers over the years. As for value, it really depends on how bad the car is. I've seen some in bad shape not even sell for $400, let alone $1500, so it just really depends. I happen to have an extra set of Mirage fender flares for sale in my garage too (sans the front spoiler). Ron Lee (above) has, imo, the nicest Mirage in existence and it was a pleasant surprise to see him post here on this site. They're fun cars!
Ken