You are prob referring to the Automotive Components (ACR) powerplus system - I have this fitted to my S3 Lightweight along with one of their full engines for about 7 years now.- it is a component package and you choose what to include and pay your money accordingly.
Consists of (e.g.) SU 1.75 carb, K&N filter, gasflowed inlet manifold, sports exhaust (silencer / muffler depending on your country of origin!) gasflowed and modified head (stage 1 2 or 3) uprated camshaft.
contact
www.automotivecomp.com (Rowland Marlow). Based near Chester, England.
I have no hesitation in recommending them