nothing wrong with trusting those who are supposedly in the know. it's when they take advantage of it that it's not right

cam would perform with twin 40's....standard fuel pump will give enough fuel, feral usually has twins and manifold going for a reasonable $$, and you know they'll be in god nik, http://datrats.com.au/ENGINES%20%26%20ENGINE%20PARTS.html
as for the su's if you can get em set up by someone who knows what they're doing you shouldn't have a problem either ?? slightly cheaper on fuel than twin 40's but they don't have quite the same audible note
one of the boys in wa had a set for cheap advertised in their virtual garage sale ??

personally .... you've got it this far - to go back to a stock cam you'd be letting yourself down
but if $$ are a big issue go for a mild street cam from a reputable supplier