Looking to get my hatch remapped in the spring and was wondering if it is worth getting a decent downpipe fitted? Will have to have a sports cat for mot so not full decat. I had heard they can really change the characteristics of the car. Don't want to ruin it. What's the thoughts/experiences on here? Also any preferences on design? Bellmouth or divorced, cat at the top or near the bottom? 

You will definitely achieve better results and make more out of the map by putting a high flow sports cat down pipe on, the car itself will create a bit of a louder exhaust note with the lesser restriction from the cat. I wouldn't say you'd be ruining anything, spool up time on the turbo will be a bit faster. Bellmouth is the common way to go unless you have a jdm twinscroll setup. As for cat placement the closer it is to the turbo the hotter it will get and better it will work at reducing emissions. The negative for that is it does take away a small amount of power and the further the cat is away from the turbo the better from a power standpoint. Most people with good high flow cats at or near the stock location get the best of both worlds but depends what you value more the environment or having extra fun in your car 

Sports cats don't always pass emmisions test 😉@Stants can confirm that.

If it's a good quality 200CEL one you should be fine... try and get one that has the tongue to separate exhaust and wastegate flow... this is the one I fitted a few months ago