What options for buggy big bores do I have?

[Marvin]

Jammin 16mm shocks are probably the best, cheapest option.

Unless, like in the UK, a complete set of XB808 shocks are available for about the same price, though you would need to buy different stand-offs. They are better shocks though. Also Xray make about 7 different spring rates, 3 heavier than stock, 3 lighter than stock. The stiffer springs can get very stiff, so you probably have better choice than with the Jammin shocks, which, if I remember correctly, the stiffest springs still weren't quite enough for a truggy, but then again I do like hard springs and damping.