A bigger turbo will give you bigger numbers yes, but it wont be a nice smooth flat power/torque line.

Using the twin turbo approach you get the boost nice a low down with a small turbo, and then a bigger one carries the boost up the rest of the rev range. good when pulling on from a slip road or such like where you need to keep it going and better for driving really as with all diesels, early pickup is whats needed.

thats very true ....this could be very intresting to see the outcome if you go this route "RANGEISM WILL NOT BE TOLERATED"
www.futuresecurityservices.co.uk
Pretlove says , '' I want my car back "

Ideally i need some pics to start off with, anyone know of anyone breaking an M57 equipped BMW and the same of a TD6 FFRR so i can see the exhausts side by side even in pic form??

If the worst came to the worst then a custom manifold could be made up for not a massive amount of money, but its the electronic hook ins that im more worried about.

Are the wastegates on both the TT and the ST engines electronic or self controlled through boost pressure? If like most modern cars its mechincal but relies on the boost being let through by the ECU this should be doable as it just requires T-ing into that line but could cause a boost spike i guess but not a massive one.

Also form what i've seen the TD6 uses a VNT Turbo, do the TT engines use the same or are they nozzle-less?

PS TT stands for Twin Turbo and ST Single Turbo