My Gt had 40 series flows on it and I liked the sound,the lower deep tone.So anyone know the difference in tone between the 40 and 44 series.Im also thinking of just doing the weld ins instead of the whole cat backs,any disadvantages of this?Kinda new when it comes to the cat backs.Im looking to do this around next month along with a few other stuff,just trying to get it all planned ahead of time,wanna get it right the first time.