You dont have to touch the trigger if you dont want to. It has two coil springs, one for the trigger and one for the sear. This goes between the sear and the anti beartrap bar. Piston washer is leather and held on by a 5mm countersunk head screw. Clean and lube. Replace piston, front guide/weight (if fitted),spring and guide. The mainsprings are quite soft in these guns, fat but with coils close together. I dont know if you can get them but I tried a old mainspring (maybe from a meteor) and it went in and upped the power a fair bit. Ive since taken it out and tried one about 1/2 inch shorter and this is closer in power to the original. Push trigger block into cylinder and turn clockwise until pin locates in cylinder recess. Replace cylinder end pin, taking care to line up the hole in the trigger as the trigger pivots on this. Fit your barrel catch spring and catch and locate barrel in breech jaws and cocking arm onto piston. You may have to fiddle about getting the anti beartrap bar into place as its quite springy. Replace barrel pivot screw and lock screw. Drop action into stock and tighten the 3 stock screws.
As said, a well made rifle and I think it will take the meteor spring with no problems if you want the extra power.