Exhaust related question
 

I have 89 190D 2.5 non turbo. ever since i have a leak in exhaust it feels like my car has gained power and fuel economy has gone up ie getting better fuel mileage. So now i was thinking to run a straight piple by eliminating muffler. I think ( i am not too sure and cant find where ) i have read somewhere that straight pipe can effect the life of the engine.
Does anybody know if it will effect the life of the engine / exhaust values in anyway???
Will there be any other affects other than noise ???

thanks for your input in advance.

any body???