You won't get much more noise from a diesel engine, especially one with a turbo. Exhaust fell off a 2.0 HDI I had once, downpipe snapped, drove around like that for a few months before scrapping the car, barely made a difference to the noise inside or outside.
Also put a straight through on a 1.9 TDI, and again not much difference in tone, just a bit more turbo whistle.
Had a lovely Milltek de-res on a 2.0 petrol Fiesta ST, sounded great at idle, raspy under load and wasn't at all unpleasant while cruising.
Had an awful Mongoose (I think!) on a 2.0 petrol GTi-6, the droning on that was so awful I couldn't drive it more than about 10 miles at a time, even on B-roads at 30mph!
There are so many variables that it's difficult to get an exhaust right first time, and obviously too expensive for trial & error. Best advice I can offer is to ask a local stainless exhaust specialist for a quote. Tell them exactly what you want - no droning but a nicer idle burble and a bit of throat under load, you can also specify the type of tip you prefer (I still like a rolled slash cut myself!) if going for a visible tip. As long as you're just going for a cat-back, I reckon that can be made up well within your budget.