get a gm 3 bar. you can order them from gm dealership or from autozone/pepboys. mapsensor for turbo transams or you can get it from aem too.

or, go to www.gmpartsdirect.com and enter part number 12223861

get the wiring harness that goes to it for ease of connection and don't cut off the stock map sensor plug. just splice the 3 bar into the stock wiring and leave the stock mapsensor disconnected.

3 bar works fine as long as you scale the map and tune it properly up to 28ish psi so you'll be fine.