I have an Imp Mk2, it’s a very nice gun, shoots very well, I’ve had it over a years now it’s it’s a pleasure to use, SFS where great to deal with, yes they are more than a a standard 99 but your paying for a tune, HW mod and screw cut gun in a congratulation you can’t just buy off the shelf.
Mine is dramatically nicer than my original 99 that had thousands of pellets through it, no doubt you can spent the time buy a standard gun, tune it new spring drop in kit have the barrel sorted and get it close but for me at the time it felt like a faf and your still left with the nasty odd holes from the sights and a potentially crap crown.
I was told some of the older guns where done by a guy that doesn’t work there any more.