Thanks for the detailed reply. After reading CSG Mike reply I did some more reading on the warranties for these two kits. Aside from the powertrain warranty on the Edelbrock, it also has a much better standard warranty (on the kit itself). Edelbrock warranty is 3 years (materials and workmanship) and only requires that the kit be "properly installed". Of course, the standard disclaimers for competitive racing use apply. You can read the warranty details here
http://www.edelbrock.com/fa20/downlo...l-warranty.pdf
The Harrop warranty is only 1 year and the kit must be installed by "a qualified motor mechanic or technician who has undertaken appropriate training in fitting Harrop superchargers." Also, there is wording about being tuned by a qualified technician as well. As found in the installation manual here:
https://www.harrop.com.au/downloads/...stallGuide.pdf
So, Edelbrock warranty is, by my assessment, far superior to the Harrop warranty. While people have reported excellent responsiveness from Harrop's customer service, the fact does remain that Edelbrock is based here in the USA and Harrop is on the other side of the world.
Ugh... tough call.
-Matt