fuel injectors, fuel pump, fuel rails, oil pump, oil cooler, all internals would need to be completely forged to be able to handle high amounts of boost.
you have to remember, the ka24e is only a sohc, so it's not exactly made for producing high amounts of power. although, considering the fact that it has an extra 400cc or so, it's still an under achiever.
personally, if i was you, i'd stick with a BP base engine and turbo that, get all the internals and all the other necessary parts needed from a BPT (Ford Laser TX3 Turbo engine), that would probably be the most effective and individual thing to do.
if there's one thing i've learnt from playing with vehicles, it's that you shouldn't mix and match parts from different manufactorer's....... mazda w/ a nissan engine and box?..... pass.
If i still owned an excel.. It'd look like this: