No the kenwoods are definately underrated, the 9104 I had only had like 60amps of fusing. The 9105 looks identical bit just with more fusing I think. Either way they are underrated at 2ohms but they do rated at 4 which is only like 500watts. Id get a better amp, while 100 watts isnt audible maybe, 600-800 sure is!!
And you can make profit on that 9105 dude they sell on eBay all day for 100-150 bucks, that's what I did with mine.