My dump tube from my wastegate re circ back into the cat but it is just slid into place...I am thinking that exhaust is leaking from this there for giving me false readings on my wideband.... would this be okay to weld together or is it slid into place for a reason

 

Well it should have a flex tube inline if its going to be welded solid.

 

its meant to be a slip fit to allow for expansion when the pipe heats up when the gate opens...if you want to weld it then you need to have flex pipe in the system or it will crack

or run an open wastegate dump and weld the exhaust where the wastegate routed into it