The Rainbow Comps for the Mk5 are Excellent Speakers, There is a Handful of cars these speakers particularly work well in, The Golf Mk5 and the BMW 3 Series are among the top 5.
I usually pair them up with either an Alpine PDX amp's or the New JL XD / HD Range of amps depending on the customers budget.
All 3 of those models of amps fit perfectly under the seats, which is easier for installation and also discreteness.
If you want to really get the best from the system using the Stock unit the perfect interface for signal conversion is the Audison Bit-Ten. It allows a completely Clean and high output signal to be passed onto the amp, clearing out all the nastiness the stock unit puts out. It can also be connected to a Laptop to allow fine tuning of the system. Good thing is it works with any stock unit from a mk5 golf to a Bentley GT. Very Cool !!!
Thanks Dalco.
Now for the stupid questions, showing my complete lack of knowledge in this area. I've been shopping around for the bits you listed above but if I am replacing the 6 front speakers, what size Rainbow components do I need? Also, what number of channels do I need for my amp? I'm looking at the Alpine PDX's or the JL Audio XD's as the HD's are big money. I'm just not sure for instance if the JL XD 200/2 will be sufficient.......... and if not, out of these two ranges of amp's what model would be good to pair up with the uprated components?
The new PDX-F4 is a stonker of an amp, This will allow 2 configurations of set up.
Either tons of power by bridging them into 2 channels, (Left and right door) or a front & rear speaker set up.
The PDX-F4 is the equivalent to the XD400/4 but on a direct comparison I believe the PDX has the edge. It seems to have just that little extra umph!! The sound quality is very good with crisp, natural sound reproduction.
I would personally use the PDX-F4 and later add in a monoblock and a small subwoofer in the boot, The JL 8" slot Ported box is very popular right now, Bags of quality, very slim at only 5.25 inch's deep and has plenty of punch if needed. It's about the size of a brief case !!
http://mobile.jlaudio.com/products_enclosures.php?menu=8&prod_id=474OR if you wanted to prepare for the future and have everything in 1 amp the JL XD700/5 is an all in one 5 channel amp that will still sit under the seat!! £500 for the amp alone though
This will do Fronts, rears & a sub if you want to complete the set up.