Bare in mind a few issues when talking about Jaycar amps as they have been tested to output their rated power but not much more at all.
There are also numerous other issues to consider when buying a Jaycar amp too. The Jaycar crossover quality is known to be "less than average" and sometimes require the user to utilise an external one. They don't have much internal capacitance, the damping factor isn't terribly high either and their THD is disasterous when they're loaded down (although this will not bother subs too much). As far as their specs go, they meet them. But when other important factors are considered, the "more expensive" amplifiers (such as Boston and Audison) provide benefits in all of these areas.