I feel your pain dude.
Your in the same boat I was 2 years ago when I bought my 06 Summit X. The original owner had taken off the Ski Doo 6.9 Pilots and put the SLT skis on the sled.
Like I said earlier, on my Rev the steering was effortless, but the sled was darty big time on the trail. When you see the shape of the keel on the SLT, you'll see it has a pretty big rocker shape to it, which gives the ski that "Power Steering" feel. I do know some people who really like the SLT for spring riding conditions.
I even took the sled into my dealer and had a tech check the sled over to make sure something wasn't out of wack on the sled. I also posted on SW to find out more about what people thought of the SLT ski. I did get responses back from several people that really like the ski, and had no, or very little darting issues with it on their sleds.
I just new the ski was not going to work for me on my Rev.The ski was very well behaved, and steered where ever I pointed the bars off trail, it was the on trail (darty) performance that I couldn't live with.
Long story short, I put a brand new pair of 6.9 Pilots on with 2 carbides on each ski. With the Pilots the sled was like it was on rails on the trail. No more darting. The problem with the dual carbides is the steering is much heavier, and at the end of the day my shoulders were killing me. I sold those 6.9 Pilots on SW, but in hind sight I should have taken the inside carbide off and tried running with just a single center carbide, oh well there in Canada now.
Heard all the good things about Simmons so decided to give them a shot. Found a nice used pair on SW. I liked the Simmons, but again the steering with the dual carbides is heavy, and the skis push in the turns. Again, I loved these skis on the trail, but they leave alot to be desired (IMO) off trail.
So the search continued. Next victim was a nice used pair of Slydog PH I picked up on Ebay at a killer price in the summer. The first ride on these skis I could tell they were not as stable as the Simmons on the trail, but off trail, way better in the powder than the Simmons. I even switched back and forth a few times last year between the Simmons and the Slydogs, and after several rides on both skis I decided the Slydogs performed the best on my Rev.
I know there are alot of Simmons fans out there, and If all I did was ride trails the Simmons would be mounted up on my Rev. I'm just not a big fan of dual carbide skis off trail.
If you go to Slydogs website they have a good picture of the keel design of the ski. I don't know how they would perform on the MT Cat, but I do know they perform well my Rev.
Good Luck on your journey.