DJJ1973, Sp's never Relased a Version of the 03' shocker that was cloed bolt., inorder to have a closed bolt gun you need dual noids and a complety different Fireing chamber set up them wut SP's had. The Closed bolt Thing was only a rumor. SP's has always used the SFT O-ring in Shockers.
As for Mr. Angery. One problem w/ the shockers that ppl have encountered is that the pins that hold the board and trigger sometimes come loose and fall out, Also, shockers can't fire super large or super tiny paint in that the SFT o-ring will break the paint
For front players, the shocker is a Great gun and there really isnt a nessesity to upgrade the Bolt unless you plan on dumping over 3-4 pods w/ a 45.Shockers Are incredibly fast and shoot pretty nice. The bolt comes similar to a matrix, but you unscrew it out of the back and it comes out as 4 peices which are easily lubed w/ some Dow 33.
Autococker is a nice gun too. You have shot both, The cockers can shoot as fast as a shocker, bu thave more moving parts and such...
It will really come down to personal preference. You have shot both markers and it's really your chance to decide. If you do get a shocker and you play front. try and get one w/ a Vert reg and vision, that way you can run a 45/4500 screw in tank and a revy if you want. Seeing the vision works pretty decent w/ a Revy, or you can switch to the good old halo and really mow some muppets.
the choice is yours, if you have $$ to buy both guns... Do that 