Defilipo make good exhausts.. But i reccomend HM headers i have run them on my Vs 5 litre and now my 5.7 and have never had a prob good down low gain in power...
Make sure you go stainless ceramic coated....
dude its your choice but theres like sooo many different types of headers out there so get a hold of some brouchers and compare the specs and price on that suits you