:shocking:OK, I got timed out on my long answer answer...so the short one is that the collapsed length is different for the 5150's vs the 5100's. It's not much: 20.37'' for the 5150's vs 20.75'' for the 5100's. In my particular application, my fabricator (JAY) did not need to cut into the fenderwells as he did with my buddy's truck for his 5100's. So if that approximate 1/2 inch of difference makes a difference, then the 5150's would be better rather than going to the 5100's and 12'' travel. But if money is the ultimate factor, then the 5100's are alright. Given the shock ends mount to the hoops. Regardless, it was just my $0.02...
Robert
