A B20 is a direct bolt in for a B18 equipped car. Take the short aluminum motor mount arms off the engine block and replace with the longer stamped steel PV/B18 arms. Use the original bellhousing and don't worry that the bottom two bolts won't fit. Don't use the PV's puny single downpipe exhaust manifold unless you like the feeling of having the engine's torque strangle itself past 4000 rpm. The SU's that would be on the B18 are perfectly capable of handling a 2 liter engine, possibly you might need some new needles. That Weber downdraft carb is adequate for a stock engine that won't be driven spiritedly, but is far from a performance item. SU's will work better on a stock engine and up through several degrees of modification, past that and DCOE Webers or work-alikes are needed. You'll need to take the injectors out and block the hole in the intake ports somehow.

Hopefully the extra pep of a stock B20 in your PV won't make the low gearing painfully evident, and goad you into fitting an OD transmission...