Hi Blueboy, your up pipe wont have a cat in, only the WRX models do so that'll save you a few pennies. And regarding what exhaust you want it all comes down to personal preference really, figure out what style you want first then pick a decent manufacturer.
Where about in Shiney Row are you from, I live just down the road next to Mount Pleasant in that terrace row just up from Penshaw Car Centre
Dan