All depends. What feel do you want?A nice snappy shot that is louder and has more kick(relevantly), or a quiet, smooth, shot with little kick.
I shoot a Rapper and almost my whole team shoots Marqs.. All the ones I've felt have shot great. Egos aren't bad at all, just not my preference.Try a few at the field or something and see what you like more.
Honestly though it would be more fair to compare a Closer to an 08, those can be gotten for around the same price now, if not a little more for the 08. 08's have less kick and are way quieter, but still snappy.
Yeah you could switch them.. But that would negate all the convenience of having an on/off asa if you actually had to take it off/put it on the gun everytime you need it. Haha.
And a direct mount rail will fit your Ion and most likely your pump, depending on what it is. I like the Bob Long Geardrive ASA for direct mount. CP's are great as well. If you want to purchase a rail, Hybrid or BL is the way to go IMO.