I am not sure about HP gains from the KKM, but I would reccommend it. I haven't heard anything about the SHO-Shop one. Did you try a search for the SHO-Shop one?

99 SVT Green/Tan #44
TH-Fix, Aussie Pipe, PRO-M, SHO-Shop Y, Borla, and other Misc.
93 Tracer LTS
Eibach, K&N, Misc (now my winter beater)

email me: keith@thinkingcapdesign.com
My Car:
http://www.thinkingcapdesign.com/KeithsSVT/