i have a gt that has an rotten egg smell and not much power I'm thinking the cats are clogged

 

How many miles on the car? Any maintenance done recently?

 

Likely yes. Any codes (check engine light on)? If so, please post what they are.

Worth noting though is that catalytic convertors generally don't go bad on their own. Generally there were/are other issues that lead to it, such as prolonged misfire condition which will cause raw fuel to make it into the catalyst and then when it gets there it ignites and eventually melts the catalyst material.

 

the car was just picked up it has 150000 miles it drives but loses power when I try to accelerate

 

I'd pull that mid pipe. Replace it with whatever floats your boat, be it another stock mid, x, H, etc..