Well I've seen a Furby vRS with a straight through exhaust, remap etc and it sounded sweet. Its a like a low down rumble like a V8 almost but the smoke was immense when he booted it by the time the smoke cleared he was gone .
Just disconnect it at the down pipe like what happened on my 1.8 N/A diesel Escort years back. Certainly got a few looks. Not sure they were admiring the sound tho.
I had a Fabia vRS with a turbo back system & race cat and that sounded pretty good for a TDI when it was under load - kind of like a loud whooshing with a deep note. The boost was up though after a remap.
If there isnt an exhaust for the 1.3, I'd get a system from a custom exhaust place and tell them to de-cat it