Audio Systems: aftermarket amp effects on impedance levels of oem amp, amp input, protection circuitry

Question
hi, i'm really new to amp/sub installation and car audio and was wondering if i can safely get away with my planned installation...
which is
http://www.e90post.com/forums/showthread.php?t=12983

I want to run an amp for my sub by tapping my factory amp output for the rear speakers and use this output as the amp input for my sub, will this work? my concern now is the impedance levels in regards to ohms and whether or not this will burnout my factory amp.I dont know what the factory amp is rated at and what it can drive. Here are the specs on the aftermarket amp i plan on using. It does have a speaker level line in, will this affect the impedance level of my factory amp.
spec of new amp eclipse 36401
SPECS:
*105W x 4 Channel Max. Power Output at 2ohm Stereo
* 60W x 4 Channel 0.1% THD at 2ohm Stereo @13.8V (RMS Continuous Power)
* 40W x 4 Channel 0.1% THD at 4ohm Stereo @13.8V (RMS Continuous Power)
* ChannelFlex Crossover
* Adjustable High-Pass Frequency (50-200Hz, L/R Independent)
* Low-Pass Frequency (120Hz)
* Adjustable Bass-Boost Level (45Hz, 0-9dB, F/R Separate)
* High-Current, High-Speed Output Devices
* High-Efficiency, High-Energy MOS-FET Power Supply
* Audiophile Grade Component Selection
* Intelligent 7-Way Discrete Protection Circuitry
* Noise Reduction with Low Distortion & Ultra-Low Negative Feedback
* High-Level Input - Add on Capability
* Epoxy Composite PCB
* 2ohm Stable Design

All i want to do is drive a 10in kicker sub...
i am using a monster power cable rated at 8gauge w/ a 30amp atc fuse.(is this thick enough?)

also will this effect my rear speaker sound quality if i'm tapping them for my new amp...I will be taping them from the speaker terminal themselves because i dont want to cut any wires. Thank you in advance and let me know if my setup will work...

Answer
that is not a  problem, just tap into one rear channel from the factory speakers,
mke sure you find the sub output i believe there are 2 in that vehicle
bass is not stereo use a hi low interface and connect both channels to the same output from the factory amplifier

good luck