Has any one used a strut brace on the front suspension? Did any one notice any results at all??

As far as I know you can't buy one for the front as its under the scuttle panel.

I've used one on a Gen2 Liberty/Legacy and could notice it. 

 

I reckon on the Octy the strut towers are so close to the firewall that you wouldn't notice it.

 

You are better off fitting a subframe bushing kit to the cross member and the rear subframe.  Maybe see if one of the Golf chassis stiffening kits will fit the Octy.

Had one on my old V70 and was a definite improvement.

As it was on my 850R but we are talking about very different cars.

Be better off for immediate improvement in fitting a RARB.

As said above would have thought your money's best off on a rarb and a anti lift kit