I had a No-Slip in the front of my last TJ for well over 100K miles and I loved it. It was undetectable when I was in 2wd, it didn't even click like the Aussie and Lockright lockers do. I literally could not tell it was there until I shifted into 4x4.
__________________ When you have a choice, buy American.
I have a d35 in my 99 and many years ago decided to put in a locker. So I put in an OX locker and a Super 35 kit. I spent a fortune on it and have not had a problem, BUT, if I had it to do over again I would have swapped it with an 8.8 and put the locker in it at the start. Probably would have been cheaper too. Bottom line...it's still a d35 and when I put in a V8 it will have to go.
BTW I have a Powertrax no slip in the front and love it. No snow in south Texas.
If your rear axle is a Dana 35c, then yes replacing the OE carbon steel 27 spline axle shafts with either hardened alloy 27 or 30 spline (like in a Super 35 kit) will make the axle worthy of being locked. When a locker has been installed, I would limit the tire size with 27 spline hardened alloy shafts to 33" and 35" with hardened alloy 30 spline shafts.
How big of a difference is there between a 27 and 30 spline shaft?