Andy,
Talk to Ned at Autolusso, tell him what you want and he can build it for you for what I'm sure would be a vastly more appealing price than Clive at CG Trading sells for.
If you haven't been to Autolusso before it's worth a trip, the unit is huge and one side of it has pallet racking from floor to ceiling and just has engines palleted up and ready to go.
They put a new (to me) gearbox on my GTA when it packed up recently plus a new clutch and a new Q2 (gearbox oil contamination) and a new upper wishbones, plus some brake discs at the front to replace my warped ones ones for a cool grand so they are value for money as well.
Sean