Review on Efficient Cooling with Four Seasons 58098 A/C Compressor: Beat the Heat! by Jeff Kern

Design not as shown. Not a big deal as all attachment points are the same, but I don't care what I got. The clutch mechanism is completely hidden within the pulley, so you can't see if it's engaged or not (and you can't check the clutch air gap). And the location of the ports on the back bothered the nut looking like a purge valve. I had to sand a small piece to fit the air conditioner. The compressor housing is rather soft metal (read, easily removed). Mounting hardware is not included and the threads are unlikely to match your original supercharger (only 2 of the 7 holes I used fitted my Ford A6). On the plus side, the soft metal meant I could easily cut holes with the original equipment. Not sure why this is pre-filled with PAG oil as it applies to cars that originally had R12. I know a lot of cars have been rebuilt but not mine. I prefer it empty so I can add my oil of choice without rinsing and discarding the PAG oil. The supercharger is noisier than the old A6 but seems to put less strain on the engine, as others have noted in their reviews. Cools well, if not better than the old A6. My system is currently under loaded and the air conditioning still keeps my car comfortable on a 30 degree day. With no specification sheet included, you must have blind faith that this is the correct fit for your vehicle. Installation and hacking instructions were included. Complaints aside, it did the job. $200 cheaper than a new A6, I don't mind the issues. And if the efficiency gains are big enough, this thing will pay for itself and then save some gas since it was used in my daily driving. If this item fails in the next few years I will update this review.