having had first hand experience in the 180B x member change over - all i can say is don't bother.

the motor sits high and forward - bonnet clearance is an issue. and i have seen another 120Y with an L18 using the 120Y x member using a different L sump ( i forget which one) and custom mounts - sat much lower and rearward.

the only bonus with the 180B x member is the neg camber on the front using the 180B control arms.

the 200B struts are too big at the top to mount inside the tower. use stanza struts with 120Y springs or 1600 struts (easy to find - everyone has swapped them over!). volvo 4 spots bolt up with a tiny amount of hole elongating but you have to use vented discs.

hydraulic clutch is an easy fix - the mount is already there in the firewall from the L14 powered sunnys and it all comes together pretty easy on the pedal side too.

if you use the 180B x member you have to lop a bit of metal off the front of where it bolts up to the chassis (captive nuts are already there for the 180B member), and the gearbox bolts tot he 120Y mount using the 180B intermediate block and a bit of drilling - the gearbox xmember sits further back now and guess what? yep - captive nuts in place for that too. it's a bit fiddly and it's a pain boltiong into place then realising you have to whiop out the angle grinder - but it's worth it.

have fun and enjoy the extra torque!!!