Hi MacMac,
As of right now, August 2013, There's 4 versions of the Syntec listed on the Babolat site. There's only very minor differences. I'm not 100% certain, but my best guess is that Syntec, (which is still on store shelves) has simply been re-branded as Syntec Pro. Syntec (old/regular) is what came stock on the older PDs and Aeros. Syntec Pro is what is going on the newer PDs and Aeros.
Syntec Touch - 2.0mm, 16g
Syntec Soft - 2.1mm, 17g
Syntec Pro - 1.9mm, 17g
Syntec Pro French Open - 1.9mm, 17g
It's worth a mention the digits above are from Babolat, and are only representative of average, or perhaps the aim point specs. It's not at all uncommon for peeps who buy 5 of the same grip, that those five grips will vary by 5-6 grams or more. Babolat seems to have better than average QC, but these 1 gram difs aren't worth stressing over imo. The thickness difs from 1.9mm to 2.1mm might be a bigger deal, but only for players who are extremely grip size sensitive.
-Jack