@@GPGarage1 cheers mate! I do have a possible recommendation though for another video for you, I've been struggling to design and fabricate my own exhaust tips, you reckon you could help?
Flow direction is wrong in your case, v shape insade must be " inlet--> < --> outlet". And shorten that pipe after v plate towards the exit, you will get a better flow.
Yes, you can also shorten the pipe after the V sheet for better flow. I made muffler like this for my e39 523i and also was working perfectly, only in my case it was 76mm inlet and 2x76mm outlet.