Expresscv

My 2017 brakes excellent, 153,000 miles and never had the pads changed , this is a dealer maintained van

my 2008 with 96,000 miles is heavier because it is a short bus -empty inside- but has a completely different feel to the pedal, not a good feel
i looked over the brakes pads and they looked newer, took it to the dealer and had the brakes flushed and they showed 11 rating out of 12 i think on brake pad thickness guessing they are relatively new
Disappointedly no change after the flush
nothing leaking etc

the 2017 stops quick not a lot of pedal travel and good pedal response even towing more weight

obviously the bus weighs more by maybe 3000 but it tends to have longer pedal travel and just not stop as good, stops if i get on it but i am not happy with the brake feel

are these different type of brake calipers/systems between these years?
pretty sure i saw 2 pistons on the inside when i was looking at the bus

wondered about going to an upgrade kit like a 4 piston set up

any info and suggestions

Triaged

Look up DOT edge codes. Chances are those newer pads are some fleet heavy duty type pads. They tend to have low friction coefficient which causes needing more effort on the pedal. Factory pads are Akebono but likely slightly different than the stuff in an Akebono box. Why not just get GM factory pads?
www.amazon.com/gp/aw/d/B001NZUYIO