As far as the engine goes, nearly everything should be the same. We didn't get D24TIC engines here so I'm not sure exactly what the differences are but I'd expect them to all be external... exhaust and intake manifolds possibly different, turbocharger set up for higher boost and compressor housing clocked differently, I believe they use a stouter fan clutch and a different oil cooler, and of course the intercooler, etc. But the basic stuff should all be the same, especially in terms of major engine parts and internals. Other major drivetrain mechanical bits - transmission, front half of the driveshaft, etc, probably the same as well.
As far as the rest of the car though, in that time period 740 and 760 are actually surprisingly different... 1988+ 760 has completely different (independent) rear suspension, different front clip/hood/cowl/windshield/wiper layout, different dash, completely different electrical system, different HVAC system, etc, etc, etc. Some stuff, like taillights, seats, interior bits, door pieces, etc may be compatible. But there's less compatibility than you'd think, given that the two cars are basically similar and share a platform.
