well, i stil have the stock spring, and stock valve and i'm running at about 225-250 psi, at around 270 fps. good enough for me.
if you want to lower your PSI majorly, with a very expensive upgrade you could get the zip kit. the zip kit changes the whole gun making it electropneumatic, meaning you wouldnt have to cock it, and you'd have a LPR and a hose running through your gun to the back. electropneumatic guns have less kick than a blowback [stock TES] because air pushes the ram forward, instead of air pushing the striker back.
the zip kit is found
HERE
for a cheaper way to lower the pressure somewhat, is a Maddman Rocket Valve. I'ts about 40 bucks and i think it's well worth it. its an upgrade i might look into eventually.
HERE's the Rocket Valve. It can come in a package there for 55 bucks, including the Rocket Valve, a spring kit, and a rebuild kit. the rebuild kit is just a bunch of the Orings in the gun that you can replace, a Main spring, and a few other stuff.
spring kits that are nice and cheap that help with the kick and pressure.