Depends on the age of the vec c, the early one was the z22se, later ones were y22se( I think) for non direct and z22yh for the direct engine. The z22se has its own dedicated forum www.z22se.co.uk, you can supercharge that engine and it gives good figures

If its a direct z22yh, best person to speak to is scotty84 as he did a fair bit on his yh including finally getting it mapped after a lot of hassle with people refusing to touch it