I can buy a brand new MTX 4405 with warrenty from the local shop for only $300 (msrp is $549). Any reason not too? The other amp I'm considering is the Alpin3 F450. Amps are very similar. I'm gonna bridge the front and rear channels to run my Boston FS60 components and power some 10" sub later with the sub channel. Basically, is there any reason not to buy the MTX amp at such a low price?