No experience with the select series, but I replaced the pickups of my Fender American Series Telecaster en HSS-strat with BKP BG50's (old set, which is BG52-set now) and VHII/Mother's Milk. In both cases a step up. Old pickups sounded weaker, thinner and flat in comparison.
Of course one has to get used to a new guitar, so it might be that you have to tweak your amp a bit to find the sweet spot for the select pickups.