Unless you wanna spend £££ on a turbo upgrade or supercharge, its a waste.
i'm a fellow st170 owner.
stainless manifold was the best mod to date.
remap exhaust manifold is all ive got.

Turbo conversion i would say be 3grand+
supercharger 2500 from the states.

decent set of springs and dampers be worth a shot.

im currently going buffy with mine.