I recently had fitted a Ragazzon cat back S/S twin box system to my 2.0 16v. It's well made and fits perfectly, has improved mid range performance (I only have a K&N panel filter fitted otherwise standard) and the noise level even without the centre box is mellow and not too loud. I can thoroughly recommend it, unlike the Quicksilver garbage that falls apart after a year.
If you intend keeping the car for a while I'd recommend going stainless
I had a Ragazzon system on my 155 but in mild steel,after 18 months it had rotted out around the welds on the boxes
The original system design also has that truly awful triangular 2nd box which is particularly rot prone yet strangely features on Ragazzon's versions too
A better option might be to have a custom built system done by Powerflow,a few folk on here seem happy with the results.............
have had powerflow fitted for about 6 months now..removed one silencer its now has a very nice sound, not to loud....i know some people have rmoved the centre silencer as well but that must be seriously loud.......build quility is great although as i said only been on a few months so time will tell on that front...another really good thing is the choice of trim options, theres some thing there to suit any taste.....
ithink supersprint has to be the best if your buying an exhaust they now do lovelly backboxes is stainless but the centre sections are still in mild but seem to last well , id avoid the dtm backboxes in mild as tend to rot a bit (im on my second) . they make a real difference in the car but are expensive ! i would love the stainless manifold they do
Supersprint stuff is readily available and good quality. Ditto Remus- try the AO shop- but you'll still need the intermediate section between the cat and rear silencer. Alternatively, CSC now also cater for the 155. These systems are all flow tested as is the Raggazzon (which may be harder to come by now?)
My Supersprint centre and Remus rear cost about £300 in all.