i've got a mk61.8si and it basically running 130spec at the mo cams etc and its ok- alot quicker than it was before but still lacking in midrange torque.
I've been told the best way to tune the 1.8 is a different manifold, pbv, unichip and possiblt de-cat.
should be seeing at least 140bhp with little lot and car thats alot more driveable i'm in the process sourcing said parts at the mo
failing that as already said wack 2litre in there 130bhp outta the box with better gains from mods.