Basically what I did but as mine is an 04 I got a plenum spacer too but i think the 313 would need upper AND lower spacers so pricey. With a 2k budget depending on what Zorst & Y-pipe combo you go for you could factor in some decent panel filters too
For reference, Milltek, 2nd hand Berks & upRev cost me < £1,500
I would advise you do your homework and don't rely on utube clips of Zorsts or you may end up with many different combinations... I know this from experience