Note: above diagram is from the factory service manual. The diagram is probably pre-production, the actual system has some variations.
Y-Pipe
Left branch: 1.875" OD
Right Branch: 1.75" OD
Collector: 2.5"ODx2.38"ID
Muffler
2.38"ODx2.25"ID
Over the Axle Pipe
2.25ODx2.07ID
Resonator
2.38ODx2.25ID