Hi, I have a ML63 in Karachi, Pakistan. I wanted to know what will happened if I take out the cats; thats if anything negative? Plus, how much of a horsepower gain will I get after removing the cats? No worries about emission laws here :-)

I will appreciate if anyone would answer my queries.

Thanks,
&
Best Regards,

Abul

I am no expert but if you remove the cats i suspect the exhaust volume will increase quite noticeably. The exhuast will also become less restrictive without the cats thus you should get horsepower increase. Whether this will decrease backpressure in the exhaust and hence marginally decrease low down torque perhaps i am not sure. I reckon losing the cats will increase hp by 5-10hp, nothing dramatic