It's been a while since I looked into this so just seeing if there was anything new on the market or OEM solutions to the following -

A while back I looked into the Honda VFR1200 DCT bike engine for a kit car, sound like a great candidate - v4 sound, compact, 170hp 95ftlb revs to 10k (not too far off a Gen 1 Hayabusa) plus has the DCT auto/manual gearbox built in. Complete bikes are now a reasonable cost and wrecked ones around with quite a few bare engines on ebay.

The big issues is it is a left hand side shaft drive system.

First off, there is a 90 deg gear drive for the shaft on the left side of the engine that looks like it may be possible to remove and add a sprocket/prop fixing, this would get the engine over on the passenger side of the car for weight distribution and be more like a standard chain drive bike engine. However, the output will still spin the wrong way round for the majority of car rear diffs afaik (there is a reddit post on some guy doing this in a moped frame, he ended putting mocking up an idler gear).

One solution would be to run an Elite/Westfield/Quaife reverse box in reverse all of the time but I am guessing they wouldn't last long. Are there any industrial reverse boxed rated to say 150ftlb and 10k rpm that are designed to run permanently ?

The second is to run a car diff in reverse and upside down but the CWP would be running on the coast side of the gears which again I am guessing may be an issue. If I were to use a BMW 166 diff from a Z3/E30 I would be running the diff well within it's power rating (iirc these has about 250hp and twice the torque of the bike engine in a car twice as heavy for the 2.8 version) so would this be much of an issue. Also will a Torsen/ATB style gears LSD work backward, I am guessing not.

Finally, could you run a 4x4 front diff like those out of the BMW x3 (3.08 ratio) in the rear, iirc these have the CWP machined the right way for reverse running but would have to forgo an LSD.

Sorry for all of the questions and waffle, but simply is there any way of running a left hand side shaft drive bike engine in a car ideally with a LSD?

from memory, for a car, (typically rear engine setup ) one way of doing this was to mount the diff 'upside-down' (obviously block holes to avoid oil draining out.)

there are a few other way ways, I think using a diff from an old audi fwd (audi 80 / coupe etc)