. . . my current build is using a Porsche 5 speed and I am using the stock design of the Europa suspension and half-shafts with both inner and outer u-joints.
I have no experience with the Porsche gearbox but suspect it's wider than the Renault 3xxx boxes used in the Europa.
If you were to copy the stock Lotus arrangement on to the Porsche box, I expect the half shafts (upper links) would need to be shorter than the Lotus ones assuming the track is to be maintained. This will affect the rear roll centre height which, in turn, will affect the roll axis.
To the extent that's a problem or not might need someone with Chapmanesque suspension design credentials.
In Richard Mann's design, the separate upper link mimics the original half shaft in terms of geometry, length & pivot points etc.
Question is will the Porsche hubs (with their c- clip design) remain in the case or get dislodged during suspension movement? Any comments appreciated.
Can't answer re the c-clip design but there's more to consider.
The Europa 3xxx transaxles all use spacers at the inner yoke such that loads from the half shafts are transferred via those substantial diff bearings.
You would need to determine if the Porsche transaxle can accept the loads or be modified similarly.
What engine are you contemplating putting in front of the Porsche box?
BDA, that e-mail address is no longer valid.