On the other hand, unless absolute domination of the FT world is your objective, a modified S400 will take you a long way in this sport.
First, swap the standard air cylinder for the FAC length one. It flattens the power curve so that it is pretty well non-existent, certainly for the number of shots in a FT course.
Second, do some work on the stock, or get someone to do it for you. Essential items are a rising cheek piece and an adjustable butt plate, and you will need a hamster. It doesn't need to be adjustable but it does help. A simple butt hook can be included in the butt plate fixings.
If it's a S400 made in the last nine or ten years it will have the three sear trigger which can be set as crisp and as light as you like. Get inside it and bin those jumbo jet tyres that fit on the pivot pins, get hold of some crinkle washers and put them in instead.
If it's a fairly new model and littered with AT hurdles at every level, just send it off to one of several very good gunsmiths who will remove the AT for you. It's not needed.
Cost, the FAC tube is about £40 and you'll need a new figure of eight clamp, Rowan do one or you can probably get one from Julian Bond. Cheek piece, it's a standard mod I do for many of our club members, the mate's price is £40, you may have to pay more commercially. This is my Airwolf. [IMG]
Butt plate, the Bisley one is under £20. Hamster you can buy from Rowan or if you are reasonably handy with some woodworking tools, make your own.
Crinkle washers are almost literally ten a penny.