you can buy a small aluminum manifold at your local pneumatic supply house for approx. $25, some fittings maybe $8, the guage? Im not sure of $ but I doubt its over $20-$30 that = $63, I think aa had them a few months ago same price $175.
On the same logic as the seller used, if I install a larger gas tank that will supply my car with more fuel also, will it go faster??