Custom Axles?

[FST4RD]

I know with a RWD if you put a bigger engine & box into something smaller eg supra motor and box into starlet you can get the drive shaft shortened to suit... not so bad.
With a FWD car if you put a different motor into it eg Mini + Vtec motor how you go about axles?
I mean do you have to get the motor all in there and then take it down to an engineering place with the CV for the gearbox and for the hub and then tell them you want something to connect the 2?
I'm not thinking about a vtec mini, something different, but this is the only thing that puzzles me and haven't really looked into....

[Bazda]

so easy, yes you install the CV and input shaft with CV, then measure the distance you need the shaft to be when the car is up on axle stands as this will provide the most droop your suspension allows. So you will have to position the inncer CV sliding part somewhere in the middle of the CV so it has enough movement when u put the car onto the ground and not bottom out inside the CV.

Easiest way is most people just use the standard shaft and cut them to length and make dummy ones. Then give that to someone to make a proper one from.