BodgerBen and Mart Mart are worth asking as they are both knowledgeable and approachable.....I have tried to get an STR0091 and have struggled to source one so have ended up with a TT10106 from Jigsaw which is pretty similar.
By way of example, Mart very kindly posted this chart comparing cam specs.....
I would deffo port the head to suit the inlet manifold and for me personally, because I love the throttle response, lighten and balance the bottom end.
To aid breathing I would put a bigger down pipe on and a free flowing exhaust.....that's pretty much it i guess and would think this'll sort you out!