Glock performance trigger is currently only available for Gen5. (edit: oops, boltgun beat me to it...lol)
Timney is nice but there are some reliability compromises.
For Gen4, if OP has no plan to switch the mag release button to the right side (for left hand person), then the best option while maintaining reliability is the combination of factory Gen3 Trigger (with trigger bar) + factory Minus connector mentioned above. This is the best factory trigger pull you can get for pre-gen5 glocks without messing around with other parts such as FB spring, striker spring, trigger return spring.
But I think the 25lb OP is referring to is that distinct tactile feeling of Glock trigger pull. Some ppl love it some ppl hate it. If you are already used to 1911/sti/cz trigger pulls, you might perceive the glock trigger pull as very clunky. It's just the nature of the beast and very hard to get pass that no matter what factory or aftermarket upgrades.