TDI 100 & 130 - just the mapping or different engine?

[drainaudio]

HI all,
Still looking at 5.5 Passat Estates and have settled on either Highline or Sport 04 - 55 plate, looking to get the best car possible so prepared to compromise on spec and colour.

Have been also considering a re-map for the added fuel economy and reported smoothness.

Ideally looking for the TDI 130 but have seen a couple of very nice Highline TDI 100's - is it just software management and the 100 is a detuned 130 or is there more to it than that?

Thanks..