Nice little setup.
The above posts cover most of it.
The Ion / Ion XE / Epiphany are the evolution of the Ion under Smart Parts.
Gog are the new name for Smart Parts in the US, but they are still Smart Parts here.
The 'pipe' barrel kit allows you to select the optimal back to match the paint you are using whenever you play, thus giving consistency etc
The 'drop forwards' on each are a bit old school and have gone out of favour, but they adjust the relative position of the cylinder giving balance and adjusting the layout for ergonomics. These went out of favour, but some people are playing with them again. In general these days people adjust positioning using a 'kick up' and/or an adjustable rail mount ASA, or just one of the variety of cylinder shapes and sizes now available.
In the final photo the inserts look right for the epiphany, but the black piece does look more like a barrel adaptor. The back should be threaded to fit the guns, and have internal threading on the opposite side to accept a different type of barrel.
Autococker / smart parts would sound like a valid adaptor as 'autococker thread' is another very common barrel thread. Many paintballers who have owned a number of guns will have acquired cocker threaded barrels
With the cylinders consider the viability of testing against remaining life.
The standard time between tests is 5 years, (but can vary in some old designs) the steelie (though may be aluminium) can be use forever, but would have to be tested every 5 years, the fibre cylinder will have a maximum 15 year life and will be marked with a final date.
New cylinders cost about £150 for a fibre cylinder and about £30/£40 for steel/aluminium
Depending on the cost you can get tests locally (and the remaining life of the fibre cylinder) will be the deciding factor on testing.
Test fees can generally be about £25, but possibly as cheap as £15 or expensive as £40. The higher cost is usual if you are sending it away
If you can get a test at about £15 then it can be worth testing the steel/aluminium but if it is more then you could just as well buy a new one
For a rough valuation / viability of the fibre cylinder consider its total life cost £200
(£150 new price + 2 x £25 tests)
Divide by 15, multiply by the remaining years to its final date
Deduct the number of remaining tests (£25 or £50)
That gives you a depreciation assessment.
Or if you say its worth about £13 per year then if the fibre has more then 2 years remaining life then it's worth spending £25 on a test
(Adjust as required based on local quoted test fees)
