m50 intake manifold leaks are fairly rare, the most common leak is the vacuum line that goes from the breather nipple on the valve cover to the couple inch long plastic coupler that connects the icv to the intake, and the coupler itself, theres no pcv plate or other ********
11 15 1 726 828 hose
11 15 1 730 507 hose
11 15 1 703 710 valve cover connector
11 61 1 738 629 coupler for idle control valve
all of that **** is cheep and usually falling off of most m50s i see