Jake,

First, The K1 and K2 are the same spring kit.

Personally, If you have the tenacity, and the drive to replace K1. Remove and replace a transmission. You can rebuild your transmission. Lots of data exist on these. I have piles of service data and links for these Mercedes transmissions.

Lastly, the American rebuild kits contain a bonus of containing the seals for the valve body. A American rebuild kit can be bought for $180 with clutches all day long. Because you live in the USA. You have access to EPC per your vin which is a priceless feature in the rebuild process.

I would attempt a rebuild on the 722.4. My first time rebuild was 722.5 which has more parts, and I did it successfully, but the 722.5 is the less documented transmission, and I used 722.4/722.3 service manuals. The 722.3 through 722.5 are very similar, and may parts are the same. The 722.5 does not have a rear pump. Their is process to doing this rebuild, and no fancy tools buy. Just 30mm 12 point socket, some o-ring picks, and a 3" PVC coupling.

It would be a good winter project...

Anyways, my $02 cents...

Best of luck,

Martin