Re: sub/amp advice
It's best to have an amp that atleast matches, or preferebly, has a higher RMS output to the sub's max RMS output. For example, a 400w RMS rated sub will need a amp that has a output of 400w RMS, or more (450w RMS at least) is preferred. The subby will still work "ok" with a little less, but as stated, will heat up quicker among a few other negatives.
Those two, that's the amp and subby will be sucking some major juice from your charging system when cranked, even at half volume. I wonder if the Telstars standard electrics can handle this?