allbutt, interested to hear what you do with this as I am in similar boat. Dogs go in the boot so cannot have a sub. Currently have OE head unit and was hoping just for 4 new speakers for the doors to create better base and overall sound clarity although realise the OE head unit might restrict it somewhat. At least with an OE head unit you shouldnt get some jockey trying to nick the unit from the car.
 
You can take high level input off the stereo.

Just a thought though, i have a sub in my boot but have quick release on it, so it's out in 10 seconds flat when I need to take big loads, or the dog to the kennels. Maybe you could just remove it?
 
Removable sub not worth it in my case as I mostly have the dog in the car with me. Its rare that I would not have her in there so would hardly get to use the sub, lol.
 
The slim sub i have got is made to go under seats etc i may try and fit it, how do you take the sub input off the headunit? Do you just cut into the wires
 
I'm sure you can take out the passenger storage from under the seat. My car doesn't have the storage box and I was considering buying it to install....
 
If you have an RNS510 then really you need an amp installed to get the best from aftermarket speakers, so if you can install the sub you already have that probably would work better for you!
 
you need to decide whether you will be amping or not.

you can get amps that use high level inputs, or get a high/low converter.

If you are not going sub root, then you may only need a small amp to get what you want.
Whats the standard stereos output?
 
Well i know that mult channel amps are alot of money and defo dont want to wire one in, i will see if the sub will fit under the seat if it does may just add that ass it has an amp built it or the high level input
 
Ok i think i can fit my syb under the seat so i am going to do that! So do i got for four vibe slick or black air?? I am not going to amp them what do you think!
 
Did you change all four??
And are you using the standard tweeters?

Yeah I changed all 4. I used the Sak3103 adapters too. I disabled the factory tweeters, but I did that before I changed the speakers because there was too much high end. Then once I disabled them there was no high end (durr) so I change the speakers lol. The vibes are a definite improvement, though.
 
Go into halfords and have a listen to them! Speakers are a difficult choice because everyone's preference is different. I still think that if all you want is more bass then install your sub, that will give low volume bass. The vibes have excellent bass but they need to be at a reasonable volume so that you can hear it!