To my knowledge there are no "bolt on" mods available for the v6 tdi yet, most bits have to be custom ! You will need injector nozzles for your power goal, the stock injectors cannot flow much past 200 Bhp. Then depending on engine code you either have a L or an E pump. The E pump has the famous 3 plunger/larger pressure head so it can flow more fuel without major decrease in pressure, the L pump will be maxed out at 52-60mg/stroke. The duration maps are stored inside the ECU so you cannot modify the fuel maps so the only way is by cheating the pump and fitting larger nozzles !
A hybrid turbo is a turbo that has either a bigger compressor or a combination of larger turbine and larger compressor ! The stock turbo has a 52mm compressor wheel which can be upgraded to 56mm, 60mm, 66mm and even bigger if "boost by appointment" is your thing ! To do a good job in extracting as much energy from exhaust and drive the larger compressor wheels then the turbine needs upgrading as well ! I used gt20 and gt22 turbine wheels with various trims and positive results and i have built many a turbo in order to get the best compromise between spool, response and fuel economy ! When you're ready to go further then let me know, save your pennies as mods for the v6 tdi are not too cheap: injector nozzles are anything between 300 and 600 quid then they will need pop testing, the turbos will require custom bits so internals from different series turbos need to be mixed in order to get the desired results and to top it up the map needs to tie all the ingredients for the recipe to work ! You will also need to add a bigger map sensor to get more scope of measuring the increased boost from the hybrid turbo and the calibrations required in order to "see" what it's what ! Personally i think that 2-3k spent on your allroad will get it on the same par with a b6 s4 with 3 times better fuel economy ! You will get a bottleneck with the clutch, intercooler and oil cooling as they were never designed to cope with 300 Bhp ! Do it right and it will be very, very reliable, cut corners and it will bite your backside !