My 40FS and 40c both have DCAEKs and polymer AEK triggers installed. Having just bought a Lyman digital trigger guage, I measured various combinations of springs and found the following:
Apex sear spring, Apex trigger spring: 6 lb 0 oz
Apex sear spring, factory trigger spring: 4 lb 15 oz
factory sear spring, factory trigger spring: 3 lb 10 oz
factory sear spring, Apex trigger spring: 4 lb 4 oz
Similar results were found for the 40FS and 40c, as expected. Apex states that if their springs are used, the expected pull weight is 5.5-6 lbs, so I'm at the top of that range.
Bottom line - the factory trigger spring is about 1 lb lighter than the Apex duty/carry trigger spring and the factory sear spring is about 1 - 1.5 lb lighter than the Apex duty/carry sear spring.
With the polymer AEK trigger, I didn't have any problems with the trigger safety catching on the frame regardless of spring configuration. Not sure it that would be case with the factory trigger.
I settled on the Apex sear spring and factory trigger spring for a nice ~5 lb pull that smooth like butter.