@Turbothinghy, there is a special demystifying thread or two on Turbos and remaps too here in TFI painstakingly drafted by our esteemed TFIan/s with extra acumen or astuteness for technical details. Do definitely browse through them to get some more answers on this topic. Search for 'Layman's perspective' on the forum. The MJD and LINEA/PUNTO/Avventura gearbox and map, has been specifically tuned or de-tuned or left untouched in ways so as to perform with utmost reliability in the upper range of RPMs i.e. on highways munching miles. There is one fundamental for a nearly lag-free experience which I believe could be achieved via a much more efficient VGT Turbo, with more fuel (or better injectors) and better exhaust modifications/implementations or even better an implementation like TWIN TURBO like on a SAAB 9_5 which used or uses the same JTD/MJD engine in a different displacement size. But that would also mean more cost and would probably justify use in an upper bracketed/segment car, where people would automatically care lesser for 'kitna deti hai.'