Well, it can be done...
If you're keeping the stock HU, you'll need what's called an LOC (line-out converter). You normally wire this in behind the HU and run your RCAs from there to the amp in the back. However, since you have the Monsoon system, you can wire the LOC in at the monsoon amp, if you're up to it (you'd basically tie into the wires coming from the HU to the monsoon amp; there's a wire schematic floating around on the forums... do a search for it). You'll also need power and ground (I suggest 8awg minimum, but if you ever plan on a 4-channel for front/rear's, you should go ahead and run 4awg... it should be no more than $1.75/ft at a local audio shop; there's also a thread for running the power wire floating around as well!) You'll also need a remote wire... you can tie this in at the monsoon amp... not sure which one it is, but I know it can be done. If it's your first time doing an install, it should take you about 3-5 hours.
I'm not a big fan of JL subs... but if you're working in a budget, it'll work fine. You may want to look into the 1000w JBL 10", or maybe even the 1200w, also the Alpine TypeR will SLAM in a ported box... but its a bit more money than the JL.
stranded... you running your TypeR sealed or ported? what kinda amp you running?