While i really love the Disc series, the simple old LK93 54cal is truly a gem and joy to shoot with the FPJ conversion. Its not the cleanest but the simplicity of the design is very nice and super accurate.
I added the Knight/Williams peep receiver site from Numrich for about $30 and i love it out to 65 yards. Its simple and has very fine adjustments.
It might be even more accurate than my GMB54-120. One range day i will devote to comparing the two.
IMO the best and cheapest improvement they can make is a rate of twist change for ALL ML calibers they offer.
Scott