What camber do you have on the front?
Dialing some more in might help the understeer issue, as it should see more grip on the front, unless you already have some on there. I run about -2.5 degrees on the front of the Syncro.
You could also look at fitting a stiffer rear anti-roll bar, but get the front end set up right first. VW liked dialing plenty of understeer into their cars in the 80's and 90's as standard.