I use a solo for both my GT3 for lapping days as well as on my kart for practice for the predictive feature because my Mychron 4 does not have GPS. It works perfectly fine and is a great tool.
The solo (at least the original) has powerful magnets built in and comes with a steel bracket I easily fixed to my kart steering wheel. I added a zip tie for additional safety to insure it stayed in place. The backing plates are like $15 each and having multiples would be convenient.
When moving between. Cars I move the whole ram suction cup when getting into student cars.
In my opinion the predictive time feature is one of the greatest learning tools it provides. You can try something different in real time and determine if it was faster or slower than your saved reference lap instead of waiting until after the session to look at data. Mychrons with GPS will do this also.
Being an AIM product all the data works in race studio.
There is a downside on the kart. The g- force Data is going to be garbage if the decice is mounted to the wheel as you need to calibrate it in a static position in the car for the data to be correct, and in the car it never moves like it does on a kart.