Both systems are loud. First one was louder than the second but both sound fantastic IMO. First system basically did away with the back box completely. There were pops and bangs a plenty it was just slightly too noisy on the motorway for me though as i spend alot of time on motorways. The second setup as I have now basically pipes up both sides independently from the mid section to the rear. I have also introduced a back box on the left hand side together with a replacement mid silencer and two booster silencers after the mid silencer. All silencers are powerflow silencers which are straight through so I have also noticed a slight increase in urgency. I also went for different exit pipes on the second setup as i feel the dtm style look better with the carbon rear diffuser.
With regards price I can't let you know what they would charge for the second setup as mine was done at cost as a favour and also as a guinea pig I suppose. I would have thought somewhere In the region of what you were quoted from the company in Birmingham.. Longlife exhausts I presume?
Hope this helps you mate