I got an Invidia Gemini from Funky Power for just over £900, sounds lovely but was a bugger to fit. I had to heat and bend one of the end pipes as it was very near to fouling the rear valance. Top tip: save skin on your knuckles & an afternoon of swearing, get someone else to fit it. That's my last, I had a nightmare replacing the exhaust on my daughters Aygo a few years ago and I wish I'd learned from that mistake. Actually, in fairness to Invidia it was getting the old one off that caused 99% of the grief, I can't fault the new one barring the minor bend needed.
Looks and sounds ace now.
Next project: uprated I.C.E. with reversing & dashcams if the weather ever improves.