You don't have to worry about the driveshaft rubbing on the antirollbar up till minus 50mm, depending on the thickness of the driveshaft.

There's two sizes driveshafts around, 42mm and 32mm if i'm not mistaken, at least for TDI's that is.
I assume a vanilla 1.6 is the same so can have both as well.

If you have the thick diveshaft you can go as low as -40mm without changing the arb links to adjustable ones, with the thin version you can go a tad lower.

With the standard shocks you can go as low as -40mm max, anything lower requires other shocks.

Mine has KW -40mm with the standard shocks on 18" wheel and there's no rubbing whatsoever.
 
sweet thanks :)

can someone explain the measurements that are in the link above please i dont understand how much that kit lowers by thanks
 
I have a 60mm drop on 18s ( 8.5 wide -using 1cm spacers so they dont rub on the inside.)

BTW : FK Coilovers
 
well 1 Inch is 2.5 cm, so ya looking about 54mm to about 80mm, or there abouts, not a ad price too, as i said B4 don't forget the antiroll bars links if your going low :D