To keep things short, I screwed up, and I'm now in need of a new y pipe assembly and catalytic converters. I found a new one on eBay for a good price but in the description, it says it is for a non advanced evap system. What is the difference between advanced evap and standard evap catalysts? Would this work for my disco with advanced evap?

 

I think the only difference is the non evap doesn't have the post cat O2 bungs.

 

Advanced had 4 O2 sensors.
2 pre cat, 2 post cat.
If you dont have inspections you can leave them off.

 

Really? It wouldn't make my ecu mad?

 

Nope.
If you have brand new O2's in the rear it will set off the CEL, nice old worn out O2's in the rear, no CEL.
Truck will run fine.