Why yes there is. Glad you asked. There is a good article on a lot of PT92 tune up at http://www.hobbygunsmith.com/Archives.htm you want November 2003 through April 2004. Also precision sights from http://www.precisionsights.com/tpu.html . All I have done to mine is replace the rear sight with the TPU model and I love it!
I tried to put a cheap BSA laser sight ($30 from Academy) on the accessory rail, but couldn't keep it to hold a zero. Very good for trigger pull practice however, it will teach you to shoot tight groups except not on the bullseye :-)