The rev3 pump is a bit more reliable than the rev 1/2 IIRC

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a popular option for the rev 1/2 was the Chris K pump

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dont know if its still available.

I would imagine that a stock pump should do you fine.

Its only really high RPM where std pumps have issues.

Gaz 9krpm is getting there! I would have though that much more than that and you'd be getting cavitation issues.

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which you certainly don't want!