Possible exhaust problem?

[reddevil]

Hi Guys, think I already know the answer, just wanted to run it past you guys first. Passed 140k in my car at the weekend, till now everything has run fine, however this morning I noticed (after a run) that the car was making a strange metallic rattling sound on idle, this was highlighted later in the day when there was a strange (but much louder) rattling sound when I was coming off the gas, when I dip the clutch and rev the engine it goes away only to return when I drive off again. I think the silencer in the tail pipe is shot, anyone agree?. So far performance has not been affected. The exhaust looks to be in good nick on the outside, is it worth buying anything or just let the silencer rot away?

Thanks in advance for any opinions.

Red Devil