After looking for an FL GT for nearly a year I consider myself somewhat of an expert
During the hunt I found cars as old as 2006/06 with the facelift front, wheels etc, but I have a feeling they may have been done by the owners, I know that it was definitely available on a 56 plate, so my guess would be 2007MY. As said previously the highline, MFD2, climatronic etc were all optional extras, we have been very lucky with ours as it has the highline, MFD2, electric sunroof, arm rest with Ipod prep, I would have liked the climatronic but we can live without it.
Another milestone was the addition of the black gloss grille and GTi style headlights with black housing, ours is a 2007/07 registered in June, bad luck for us is the change happened in August of the same year.....
But its nothing a roll of gloss black vinyl and an upgrade set of lights couldn't solve.
DPF is a diesel particlate filter, you need to be careful with these as they are required to reach a certain temperature to re-gen themselves to work effectively (generally a journey of 10 miles or more) they were fitted to the PD170 but I did see the odd PD140 with them (rare though). Best practice - imho of course - especially on the PD engine which it was not really designed for is to get a delete pipe fitted and have the car mapped.
HTH, Lee.