Gary, Hawk,
It is a stunningly impressive little beastie. I agree with you Hawki, the seats are the weakest part of an otherwise very, very good machine.
The ride and roadholding are approaching Aero Chassis cars.
BUT.... to change I'd need to find £25k. It makes no sense, financially and the seats and brakes in Tarka are way better. With SSL's magic the ride is also better.
But if I got one as a competition prize I'd keep it,.... wouldn't take the money instead. A manual PlusFour with wire wheels and Tarka... what a pair.