relentless vs miltek 3inch down pipe plus de cat SEAT LEON CUPRA K1

hi

was thinking about getting a ceramic coated relentless 3 inch down pipe with de cat for my cupra K1. £300 it is. i also passed by my local tuning garage he said he could get me a miltek down pipe with de cat for 345£. just wondering what i should go with? any suggestions, or any other makes that people know are good/better i already atm have a miltek non res cat back fitted and revo induction kit. its not yet mapped.

also what could i look forward to in terms of power/sound improvement when the down pipe and de cat is fitted (and mapped ofcorse) ? any pops and bangs? i had an astra VXR before this and sounded good to me had a full 3inch scorpion exhaust on it and other mods.anyway, videos welcome if you have any.

thanks

yeah so ive just bought the relentless 3.5" downpipe. any had a full exhaust fitted to a cupra or k1 and had pops and bangs.
i only have a non res cat back fitted atm and induction kit. how would the down pipe make a different power wise and sound..