I bought the cheap Frontier 60 inch finish mower last year for my 3320. The dealer was closing them out and I got it new still in the crate for $900. I said I wanted the I-match kit and he threw it in for another $100. I know the list was just over $200. I wondered too why it was so expensive.
I found out there was a lot more to the kit than I realized. It is quite a deal changing it over to the I-match system. There are several pieces including floating arms, pins and a floating third point arm. I also have a MX6 heavy chopper mower that has the I-match system built right into the mower. The MX6 hooks up like a dream. The add on kit isn't as quite as good. It may be because I have the lower end unit but the two bottom floating hitch brackets are so low to the ground you can't just back up and hitch it up like other I-match implements. You will have to put your arms down all the way and get close then get off the tractor and put the mower bracket over top the I-match. It is not difficult, just not what I expected. The upper link it a bit tricky also. It doesn't just fall into place like the MX6. That must be manually fitted also. Another thing to be aware of, the I-match on this finish mower required a longer PTO shaft. The dealer threw it in with the package, I don't know if it is actually part of the kit or he just threw it in.
I would probably buy the I-match kit again because the alternative is taking the I-match quick hitch off the tractor every time I wanted to use the mower which is also a hassle. The only thing I may would do over is get the better, heavier finish mower. I got this one because it was such a good deal. The heavier units have a faster blade speed and do a better job of cutting.