Front and rear RS diff swaps

[metaripley]

I can pick up a Evo 4 RS diff and a 4-9 front diff.

1st i want to make 100% sure they will drop into my housings.
2nd I want to make sure that I am not wasting money on something that is not really the best way forward.

I have a Non-ayc (plain open) diff on my 2001 factory manual.
So will the evo 4 RS diff swap over? (can only find a bunch of info on AYC diffs)....
The 4-9 front diff should swap over according to my research but confirmation could hurt.

2nd, is the 4 rear diff a good way forward or are there better options.
I can get the set for 1500 euro, where I also found a 8 RS diff where they asked 1500 for the diff alone.

Much appreciated!
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