Title says it - gotta replace a very old booster after already replacing the very old vac. Vac is a polaris TR28P (been very satisfied with it so far, it does did a great job with pine straw, before the pump eviscerated itself). Polaris recommends their PB4SQ booster. Claims of efficiency seem to be supported by reviews. Anyone have anything good or bad to say about it, or have another they can recommend?