4.0ltr V6 exhaust noise after hi-flow cat upgrade

[Aaron79]

Hi all, wondering if anyone has had some experience with my issue.. I have had my 2006 SR5 V6 for 13years, I remove the rear two cats a few years ago, years prior to that I fitted redback headers. Sounded sweet, but recently I Had replaced the front two cats with hi-flow ones. This sounds awesome when idling or when I open the V6 right up. But between 1500 -2500rpm, the right side sounds like there's an exhaust leak??? I've pressure tested complete right side manifold including the header. It's driving me insane. Wondering if someone has had a similar problem, and how'd you overcome it. Cheers guys

[jeffy]

put soapy water on said area where there is suspected leaks, if it bubbles, get it welded