Hi,
After years and years of wanting an impreza I have fianlly got a 51 plate (new shape) wrx today .

I have been reading through how tune it but I'm a bit confused.

Firstly am I right that the best and cheapest (I don't have much money left) way to start is a panel filter and exhaust?
If thats right which is the best exhaust (I expect it to be louder but I don't want boy racer noise, I'm 33 years old with 2 kids and like my neighbours!)
Do I need the downpipe replacing with it or what.

And which filter is best?

Any advise you can give at all will be really appreciated as I really don't have a clue.

Thanks