From what I've seen and heard (albeit in the past), they just used a windsheild washer pump which doesn't produce near enough pressure/volume to do the job correctly. Keep in mind, if the kit is cheap enough, you can replace the pump with something more suitable for $65-$100 and utilze the other parts of the kit... but it'd have to be pretty darn cheap!
More $$$ but SMC seems to be THE way to go!