Next to the scope, the best thing I did to my Kral was to send the fill port to Troy Hammer for machine work to make it fit a standard foster fitting. It cost a few bucks, but it did away with the proprietary fill adaptor.
I just got the Athlon Argos BTR Gen2 in today 6-24x50 and man it is a really nice scope. I have the Athlon Midas Tac 4-16x44 and is an amazing scope. Wanted a little cheaper scope for my .22lr and went for the Argos. I had a Gen1 when they first came out and was a nice scope. The Gen2 is a much nicer scope than the Gen1. The turrets are so much better than they used to be. Glass is great. I'd highly recommend one.
Thanks everyone for your comments... I decided on the Athlon Helos BTR 6-24x50 and just received it to day. The glass on the Helos seems similar to the Argos, but the Helos cross hairs are thinner than the one Argos BTR 6-24x50. The turrets look beefy to the Argos and has a defined clicks on the turrets are great. I can't wait to mount it and sling some lead.