The Silent SR suppressor looks to be running around $390 (from GOOGLE search). The Silent SR-ISB is the integrally supressed barrel and shows MSRP of $629
The SR sells for around $349-$399. The ISR will likely be $549+. It will cost more then a mist and limit your aftermarket stock options. I might build one as a demo but the Mist is a killer can and works great in the Magpul stock.