Up Graded - Performance Damper when do you do that?

^^ good post.
I would say your at the point where moving from the OE replacement dampner would be definitely be a good move.
Not apples to apples but I run a Romac elastomer on my hemi 6 and it's a pretty good unit - it's about 3x wider and 2x as heavy as the OE replacement unit. These engines have pretty bad harmonics going on around 5800-6200rpm and the heavier dampner shifts this point further up the RPM range. I imagine the slant would have a similar "unhappy spot" that you need to tune out of the rpm range your using.
I would recommend a fluid dampner if they are available within your budget - it's what I would be running on my engine if I didn't have to buy a big $$ adaptor to run one.