How can I test to see if the ragjoint is old and needs replacing? The car feels real loose and tracks every root possible.

You can pull the knuckle off and grab the two sides and try to twist it. It should be solid. I can bet you money that it is bad. Even my prior 97 had a bad one with 54k miles.

get a LS1 car steering shaft.

100%
some say the shaft will not work but it will just like everything else a little mod time for a mod worth having.
the column end of the shaft will come off(it is splined and spread) at the end so it will not just slide off easily. i used a peanut grinder,removed the spread out portion and re clocked the knuckle tapped it back in place and used 2 small tack welds then reinstalled the new shaft.works way better now steering feels sporty instead of soggy,15 min worth of work and 10.00 for the shaft.

mine was 100% bolt on, no modification at all took 10 min.

steering wheel was not cocked to the 11 o clock position when the shaft was installed?
i did my 95 and 96 both required the mod i wrote......

You can always get a fbody 4th gen rag joint eliminator...i have one for sale if your interested. PM me.

nope.

even if it was I would get it straight from the alignment.

Where would one get a hold of a good LS1 steering shaft for a '96 SS Convertible?

Is this mod "safe" ? I understand it's not necessarily 100% bolt-on but I'm willing to make it work if need be.

Also I've tried contacting Unbalanced Engineering and they're not answering to mails, and I didn't find any phone numbers... Is anyone else making such kits?

Flexus, I'd keep trying to contact UE, maybe he's on vacation or something, but he makes good quality products.

There are f-body specific dismantlers here, but I forget their names. They should be able to supply you with a steering shaft.

I decided to stop spamming them with mails and found some pictures of a rag joint eliminator kit install. Figured the kit ain't all that and made myself one just like in the pictures.

Took out the rag joint disc, had someone make a replica out of some solid alloy, got some nuts and bolts and there you go, homemade eliminator kit

I can't tell you how big a difference there is with this instead of the crap joint. It's freaking awesome, steering is so connected. The play I have in the rackandpinion (which I think all units have a little bit of) isn't felt at all when driving, it's perfect.

Had I known about this ragjoint problem I would have done this a long time ago...

Now that's the ideal solution, do it yourself.