the stage 1 kit doesn't run well. they only use a rising rate pressure regulator to address fuel needs. they do no programming whatsoever. that does not adequately deal with the fuel needs. also, it does not address the part throttle/on boost lean condition at all. further, they drive the belt on the smooth side, which causes belt burnout. they change out the dual speed dual fans for a single electric fan. that does not provide as good of a cooling system as stock. every one of these kits that i have heard about has had issues with this. even the guy who had a magazine article written about his car has since gotten rid of the kit. a guy in australia fought for over a year, and spent over $10 trying to get the 928MS kit working right. ultimately he yanked it off and bought one of mine. he has since bought another one of mine.
the stage 2 kit had to use a standalone computer. i cannot speak to how well that setup runs, but i can bet that they did not create the "silver bullet" map that i did, which addresses the part throttle/on boost issues. also, they use the 3rd generation injectors, which i tested and proved to have issues, due to the size of our pistons and shape of the combustion chamber, which is why i went back to the 1st generation injector design, and had larger ones made for my kit.
in developing my kit, i had to adjust 20 of the 142 maps in the computer. anything less caused less than desirable running conditions. the 928 kit is incomplete. that's why i didn't buy one, and developed my own. i wanted to, and begged him to complete the kit properly. i had my big fat checkbook revved up and ready. he refused. i had no desire to design one, but because he refused to do the job right, i had no choice. in the end, i am glad i did, and am proud of the fact that it is so complete that it is 50 states smog legal.
seriously, on top of the fact that the kit on there is problematic, the car you are looking at has an awful lot of miles on it, and is not well optioned. the car i linked to is a LOT better, has half the miles of the other one, and actually runs right.
you've heard the old adage "pay me now or pay me later"?
there is a LOT of information here about these kits. do yourself a favor and read up before spending any money. you won't regret it. also, you can ask the 60 some odd people here who have my kit about how well it runs. you will be hard pressed to find anybody with the 92MS kit. i know there are a handful of them out there, but as far as i know, there is only 1 of them running, and it was the test mule car.