The cars are pretty much identical. I think the tS gets like... heated wing mirrors, some slightly fancy dampers and an STI badge on the steering wheel. It is a little bit odd that they don't offer a manual tS but that's the reality of most car brands and their extremely limited customisation these days.

Why can the 2.4T Premium be configured as a 6Speed Manual but not the higher spec tS?  

You can adjust the piston position at the top of the clutch pedal. Move it towards the firewall. You might want to check that the hydraulics are working properly first though.   Also make sure not to adjust it too high, because then, when you push the pedal to the floor it can over extend the clutch fork and the master cylinder.

I have 2012 impreza WRX-SE crouching tiger ( The orange one ) .     the clutch pedal is " biting " right at the bottom  i.e  as the pedal is pressed right in . is there a way to adjust is so its a bit further up in the stroke of the pedal . Any help would be great this is my second Subaru and love these cars .   My car is like this one . mine is number 2 of 10 for New Zealand https://autotrader.co.nz/car-reviews/subaru-impreza-wrx-crouching-tiger

Think I joined 2005/2006ish... recently back into the Subaru ownership game too, trying to relive the glory days! Have added a 2004 WRX STI Spec C WR-Ltd to the fleet.    First Subaru was a 2004 WRX WR-Ltd, then a 2003 Spec C that got turned into a race car and written off at the ITM400, then built a 2002 Spec C into another better race car which I sold post Covid and naturally have regretted ever since! A reunion at some point would be good value.    BT