Oops....
IMO Smart parts on/off arent very good. I've seen many examples of them not working very well, so if your gonna get one, go for a CP Oops (on/off/purge stystem). It's a bit more money at about £25, but you get what you pay for, which is equally true of the SP on/off at £13. Read my Ion up's sticky and take note!!
Firebolts are great! Look on ebay for a one slightly cheaper than £30 though. I've got a firebolt and with my lucky stages 2 and 3 I run at about 120psi @ 290fps due to a much reduced dwell.
Oily, I know your the lord and master of modding and upping Ion's but don't stock Ion's run at about 160psi at about 290fps? Typo maybe?
As for firebolt i have one and its definitly lighter on the paintballs but when i fire to empty my air tank it leaks the last about 100 psi out
I think the reason it leaks this out is becuase the firebolt can't reset properly at that pressure (i.e. 100psi), and so the seals are not made and thus air leaks out.