Its not real hard to do altho you should think well about what speakers to put in, if you are going to use 8 speakers (2 bass, 2 rear, 2 mid and 2 front) then you should get an extra 4 channel amp to power the rear and mid speakers, you should check if you radio has HP/LP controll on it so you could set the front speakers to HP making them go a lot cleaner and louder just because you simply have less vibrations on them (no bass)
I would still set the rear and mid speakers to HP and use the frequenty level controll to give them a little bass. The connecting part is easy depending on what already lies in your car. The RCA (data) cables you can extend from your current PG unit towards any new amp, the remote you can just tapp off so it has two ends. The ground shouldnt be a problem either since you probally builded your **** in the trunk and therefore have enough points to ground on. The power cable on your current amp is probally 10mm, if so you need to put an extra cable that matches the start point of your current power cable. If its 15 or 20 then you can just unplug it from your current amp, put it on a splitter block and then take two cables from there.
If i'm correct your PG is a QX model, you would end up nicely by adding the PG-QX300.4 to your set
Small hint: Your current amp probally runs on a 10mm or smaller cable, if so dont place a new one but take the time to remove that one to put in a cable thats 20mm round
Editted: just read you where going to use 8 speakers AND 2 woofers.... personally I would go with 4 or 6 speakers to start with, its a lot to power up in one breath if you go for 8... The fronts can always take care of high and mid sounds but if you do the same on the second set of front speakers (probally located somewhere at the back of the front door) you wont get a real nice sound... you would have power in the back and high chaos in front
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