I think the 1X and 1Y intake manifolds are pretty similar, though the 1X has only one port for a pcv input that actually matches up with a stock 1.6 PCV puck and hose. IIRC, the 1Y has a passageway cast into the manifold and some other flanges, etc.
I know for a fact that the 1X intake manifold when used in a transverse way on a caddy, puts the aircleaner connection on the passenger side, so its nice for an aftermarket cone filter after relocating the fuel filter forward on the fender.
Cost was $65-75 and he wasn't too keen on removing from one of his 1.9 n/a engines tho...