From my point of view it is completely pointless tuning it any further anyway, the bloody thing hasn't got the rev range as it hits the red to quick already in 1st and 2nd. More power would make it virtually useless at the lights with out regearing.
Roll on the next gen with common rail. As for the DPF, every new diesel in the vw range are now fitted with dpf from what I have read and no doubt seat will be following very soon to include the 140 etc.
The newer engines look to be less and less tunable for the future as well.
I dont understand why people dont just go and get the cupra for the extra power, cause your not going to get a significant difference in economy once you have tuned it. (remember once youve tuned it you will be even LESS likely to drive sedately....SO WHATS THE POINT)