If you get a d/p and intake, that will mean you'll be best off getting a stage 2 map off Giac, if you get an uprated HPFP, then you'll need a Giac pump map etc etc.
If you fit a downpipe and hiflow cat, there are some people that end up getting the engine light coming on. mine didnt, but there are a few people who have had it happen.
The noise alone off the exhaust and intake is a nice enough benefit