Ruger P91 Trigger Help?

My friends has a P91 in 40cal. After shooting a few of my guns, he is more unimpressed with its trigger than usual. I know the deal with Ruger and their triggers and I am pretty sure that not much can be done for this P91 trigger, but anyone have any experience or suggestions? I haven't seen any trigger kits, but maybe they exist?

Thanks in advance!