Some 124's don't have pre-cat's from the factory, regarding the rear muffler don't cut it off with out having a good replacement around it will be too loud. The center resonator as noted above is the key thing to remove. I have seen some side in side out mufflers for sale but the TE muffler is an odd shape. The down pipe mod and resonator will make a world of difference. I have removed the resonator on wagons, CE's SEC/SEL and 129's to everyone satisfaction.

Steve