I agree with the above except for the wrench sizes. I am pretty sure it requires 1/8" (to remove the center portion that holds the o-ring and contains the filter) and 6mm to remove the DIN retainer itself.
An 1/8" allen wrench works fine as torque is not critical (just don't over do it - snug is enough). However the 6mm need to be an allen head socket with enough reach to get to the bottom of the DIN retainer - some short reach allen head sockets will catch the hex fitting, but not enough of it and it will strip. You need the allen head socket as you need to properly torque the DIN retainer. 22 ft pounds is in the middle of the specified range.
So you need a 1" yoke nut socket, a 1/8" hex wrench, a 6mm long reach allen head socket and a torque wrench, plus the Scubapro universal DIN conversion kit.
The kit runs about $45.00-$50.00 on e-bay or around $65-85 at the local dive shop which while more expensive is still cheaper once you consider the cost of the tools you'll need to buy and the shop should install it for free. If you have tools or like to buy tools, DIY makes sense, if not, you are better off having a dealer do it than installing it without the proper tools.