I own the modx 7, and wish I had the action on the montage synths....
Personally I don't gig with ANY 88s so that's a personal thing
I own a (malfunctioning) pc3 and that has soured me a bit on Kurzweil. A bit harsh maybe as every model is different, and any keyboard can have issues. It is/was a GREAT all-around keyboard that would do very well with 80s stuff I think...presuming here that the Forte is the pc3 and then some.
Then again, my modx has that FM engine in it that would really help if you were going for a lot of 80s DX7 patches. The only weak points to me so far are: b3 organs, and analog sounds. The former probably not an issue with 80s so much, the latter maybe so. I have not really tried to get in there and do much programming in fairness...but when I was trying to find a decent Moog solo patch I was very underwhelmed. I felt my old pc3 did better with analog-sounding stuff. Of course, you have the Kronos with all its power to help make up for that if you find the same thing!