[87 GT MUSTANG]

ok i just wanna no what the deal is with this adjustable regulator, i see everybody switching there fuel pumps from stock to around 155gph-190gph, what exactly does this regulator do to help this change in gph, does it give more hp or trq at all or is it just a simple upgrade from stock, also what would a 155gph fuel pump and regulator set me back canadian. Thanx