have any of you noticed a noticeable change i performance or noise or roughness by using 87 octane (R+M/2), rather than 93 or 91?

Of course... Your car should be more rough with 87, less hp/tq... less smoother...
I wouldnt recommend... If it happened, u better mix that with the highet Octane available.

Thanks, i had felt that after using 87 octane once that the engine seemed rougher and weaker but i wasn't sure if it was just me since i have only had the car for 2 months.

ya... it will make it feel rougher and it also isnt as good for the engine as it isn't as clean burning and stuff

__________________
2005.5 A4 2.0Tq 6speed

-Snub Mount
-Carbonio CAI
-Smoked side markers
-Smoked front bumper reflectors

The reason they give the minimum octane rating is because everything in the engine is tuned for a minimum octane rating. Its never good, especially in a turbo car to go below the minimum value. Especially only to save a couple bucks at a fillup.

__________________
2008 A4 2.0T 6MT S-Line Ti Pkg

ya... and will probably cost you more down the road when you have a problem if one comes up

__________________
2005.5 A4 2.0Tq 6speed

-Snub Mount
-Carbonio CAI
-Smoked side markers
-Smoked front bumper reflectors