Sounds like a bad part. Mine was stiff and took some leverage to compress when I put it on, but it did compress with a standard size wrench.

Could it be assembled incorrectly? Likely not, but part of my belt-throwing problems early on after my swap stemmed from a poorly assembled tensioner that I bought as a kit and was in too much of a hurry to check before I put it on the motor. Check your belt part number too. I was sent two 4.4 belts before I got the correct 4.6 belt.

How does it compare to the old one? Same uncompressed length?

Firstly, thanks so much for the replies and help. I managed to compress the dampers but not in a bench vise. I did some caveman type stuff and used the bottom of an iron fence and the handle from one of my floor jacks as leverage. Dampers were incredibly stiff, the a/c damper felt like something freed up after several compresses and now feels like what should be normal tension but the main damper is still crazy stiff, I dunno if they overfilled it with fluid or what. I’ll try a few more times and see what happens, if it’s still too stiff then I’ll just get an INA damper from FCP Euro.

The a/c assembly came in the correct orientation but I had to switch the damper around so the rubber boot was on top for the main tensioner. The belts are Conti but I’m looking to get new ones, I read Bando is good.. hopefully they come in the correct sizes. My main concern with the tensioners was fear of shredding belts and potentially causing other damage if they weren’t dampening like they should.