Hmm, I think the 3100 was a pretty good engine. My wife'* '94 Sunbird had it and was running fine at 100K miles when we traded it in. And my Cutlass that I still have has the 3.1 and 143K miles. The only problem I had with that one is the usual intake leak that I had fixed at 80K miles.
I was going to mention the strength of the 3.0 Vulcan motor too, but it was Cody'* thread. Since you brought it up, the vulcan motor has great mod potential and is a good strong base for power adders, including superchargers and blowers.
And Cody, you should drop an L67 into that Regal..