I bought a MM 071 sound chip earlier today off Mr Graham and I've fitted it to loco 085,
First impression is that its a good sounding chip with lots of useful functions,
The engine sounds a lot like the refurbished engine that was fitted (and still is) to loco 076 and 112 as when the loco is idling its in a high rev,
One of the functions-F4 is used for shunting at slow speed but with a high engine rev-which I like,
Also when idling a compressor noise can be heard every so often which in my opinion is not quite right but i can live with it,
I would give it 9/10.
086,085 and 077.