Mark,
I suggest that you call either Carlos at RTI or Bob Price to see if that pump will work OK.
The ZP28028 is for turbines up to 80N and it puts out 300 ml/min.
The ZP30020S is for turbines up to 170N and it puts out 650 ml/min.

It looks like the ZP30020S puts out twice what is needed. The ECU may be capable of adjusting to run it at a lower duty cycle. Also if you read my post above you should get one with an EMI filter, or add one to the pump you have. The specs are on Hausl's web site
http://www.modelltechnik.at/eindex.htm

Joe