it was good enough for turbo technics. me an a mate turbo'd an xr3i in 2 hours. janspeed exhaust, standard intercooler, t3 turbo, took head bolts out an slipped in a second head gasket for good measure, s2 oil feed, tapped a hole in sump for oil return(never removed sump)

drove well for over a month and boosted to 6 psi. turned boost up to 12 psi and it fell to bits around us!