Amp guru's, I need some advice.

Currently on my tower I am running 4 speakers that have an RMS rating of 175w @ 4ohm.

Powering each pair of speakers I have a Soundstream Tarantula TRA 800.2 The amp is rated at RMS 2 x 200 at 4ohm and RMS 2 x 400 at 2 ohms. Which means I am getting 200w per speaker at 2 ohms, right?

I want to increase the overall power and sound (loudness) of the system. So, would I be better off switching to a 4 x 150w @ 4ohm amp?

I was looking at the Zapco 1000.4, Alpine Pdx-4.150 or the Planet Audio BB4.150. All of these amps are rated at 4 x 150w @ 4 ohm.

I was hoping to not double my amps and just replce my 800.2 that is why I am looking at 4 channels.

Any ideas or thoughts?

Thanks.