I bought 2 sets for each Spark....
The back set is VERY EASY....all you have to do is remove the 4 bolts that hold on the back grab handle that is behind the seat (obviously take the seat off first) and you install into that piece...I brought each mine into the house and just did it while I watched tv....was very easy...
The front one was the biggest pain ever...in fact, I haven't even done the second front because the first one I did was such a pain, I am procrastinating doing it...you have to mount them in the ski, and getting the back screws in and getting a wrench on them was awful...you are pretty much doing it by feel since you can't see back there and reach it with a wrench at the same time...I used a socket wrench fyi...
You will need a box cutter also to cut out the little plastic plates...
Oh yeah, and when installing the front one, you have to remove a trim piece which the bottom side (closest to the front of the ski) is a plastic rivot type of holder....you have to pull the screw out which then loosens it on the inside...
But i will agree with the previous poster, the front is a straight PITA....
The system once installed works very very well, i will admit...