1740 Adapter plate and drive shaft

I got this 1740 a couple of ears ago. First I love this machine. Amazing engineering and yet no degree in electronics needed to work on it. Yea parts can be expensive and a little scarce. But hay this thing does every thing I expect of it and then some.
I have been noticing some excessive vibration in the drive line, needed to finish a small project so I have been keeping the RPM's low to prevent the vibration. Wasn't sure if it was coming from the Adapter Assembly drive plate ( p# D64523 $1,300 ouch ) or the rear end yoke that hooks up to the gear box. The variable drive speed control had been leaking also so thought it would be a great time to get familiar with this repair. I already had purchased the kit for the vari-drive. Got the parts off and the adapter plate is loose in every way possible and the bearing end of the front end yoke is a little beat up. The other end yoke looks a little worn but seems serviceable.
So now to my question.
I can have a solid adapter plate made for about $650 including a new front end yoke. Has any one tried this and what problems would going rigid create? I notice that the 1737 has a solid front yoke. I wonder if that can be adapted to this application?
Whew that was a lot of words. Any input would be appreciated>

Here is what it looks like so far. Yea I know its not case yellow/orange. All of our equipment is painted the same color.
Only 3 modifications so far.
Replaced the factory belt drive cooling fans with two electrics that are reversible. So in the winter I can blow hot air into the cab.
Wider tires. Full set with rims delivered for $950. Any one need some old case rims?
Also had a local fab shop build me an adapter so I can now run the new style skid steer attachments. Got a medium duty Grapple/Rake we move a lot of rock and trees.

Iv'e read a lot of posts were people don't like these, leaving me confused. Did I get the only one that works good or are all the rest BST (beat to, you can guess the rest) Look forward to hearing input on my previous question.