SLR 105 upgrades

[vancouver_sc]

I want to know what improvements would you recommend to a SLR 105.
Currently I have this:

-systema barrel
-systema turbo motor
-systema cylinder kit
-systema 130 spring
-CA helical gears
-polycarbonate piston, 2nd tooth removed
-7mm metal bushings

It works decent at this point, but I was wondering what should I expect to break and what can I do to improve either precision or fps.

[Donster]

systema barrels suck. get prometheus or KM. Madbull are also supposed to be pretty good.
you can get a guarder or modify cylinder kit. it will be cheaper and in terms of quality or performance, be either equal to or better than systema
what fps are you going for? the 130 spring might put you over field limits

[vancouver_sc]

systema barrel was the only avail at that time, comparing to other 6.03(but probably not prometheus) it seems better