Had a S400 in a Paul Wilson stock myself which never let me down. I put Sightron SIII 10 - 50 x 60 on it, but never felt the rig was a target rifle. Decided to buy a Steyr LG110 and never looked back. Only down side to me is that the hamster is not low enough at all. A guy at Emly Moor made me two aluminium posts to lower it, now it is magic.
It did take me a while to get used to. Out of the box it didn't shoot as easily as the S400, but then again you don't jump in a Ferrari and get all the performance after driving a Ford for a long time.
I know what you mean when you say "lusting", I think it is one hell of a rifle and would not swap it for the world. I am sure you will think the same after a couple of sessions with Garry's. What an offer hey?