Im not to familiar with Fitaski stocks, but a guy I shoot with has a Wenig stock/foregrip on his 391 and raves about it all the time. You can get a "do it yourself" kit with standard wood finish and a monte carlo stock that you have to sand/fit/finish yourself for 150 bucks. His standard wood was not the most luxurious I have ever seen but they have many other grades. Their definatly worth checking out.
Wenig.com
-Ross