I'm not sure if this should be posted in another forum or not, so please bare with me.

I have a 2003 Nissan Murano w/Bose and I am replacing everything but the Head Unit. (Can't replace because the radio's controls share the same circuit board as the HVAC controls.) Anyway, I am using a prototype plug-n-play high to low level convertor that will give me 4-channel RCA outputs. Speakers being run are 6 1/2" component set for the front and 2-way co-axial for the rear, along with two 12's.

As far as powering the mids/highs, I seems to be in a dilemma. I want to get Kicker KX series amps, but the question is which one?

I am deciding between:

KX300.2 which could power 150 x 2 @ 2 ohms, .2% THD. (No Fading) $162

KX600.4 which is 75 x 4 @ 4 ohms, .085% THD. (No fading, but can use the front and rear gain controls to lower the sound from the rear fill + fan cooled) $220

First question is: Will the higher THD in the 300.2 be noticeable?

Second question is: Will I really need to lower the rear fill if I use the 300.2?

I'm kinda budget shopping and was wondering if it was better to get the 300.2 as opposed to the 600.4. I figure that since I'm using an OEM Clarion HU, then there is no need buying all of this great audiphile stuff if the source isn't clean, right?