The Extreme conversion kit can be had new around $80-90. Maybe less if you check auctions. I had the Magnum DISC, it shot well. I traded it off because the stock and palm swell just didn't feel right to me.

It cleans about as well as any other Knight, you do have to use the c-tool to partially disassemble the bolt for cleaning... not a big deal really. It is easier to clean than some and harder than others but not by much.