It could be a headgasket issue and the white smoke you said it let out is evidence of that. White smoke is coolant, blue smoke is oil, black is fuel.
A compression check '"may" tell the tale.
There is no 2.3 specific kit. Just get one for a 5.0 or a universal kit. Make sure it's a wet kit. With a proper tune, you should be able to run up to a 100-125hp kit, though a 50 or 75 kit would be safer, especially if using pump gas.
He can't use any high performance parts or "non-stock" parts as stated in the rules he posted. I do think a 2.5L crank would fit in the rules though since I think they were in Rangers in 93. Otherwise, I'm not sure what you are asking since it sounds like they want bone stock engines...
They are the same engine so it doesn't matter. Yes, it will be streetable.
If you've got 5k to spend, might as well get a standalone ecu (if you know how to tune them).
The only timing on the DIS motor that can get screwed up is the cam timing...which is just a matter of lining up the cam timing pointer to the mark on the cam pulley while the #1 cylinder is on the compression stroke.
(Look up cam timing in your manual)
I didn't say you couldn't use any of it with my header, it's just that the header moves the turbo so "something" is going to have to be modified.
The power between the two coldair systems should be about the same.