Turbo Technics makes the Turbo that both Allisport and BAS market. Take your pick, it really comes down to shipping. Ive personally found Bell Auto Sports to be more responsive so that was my route. Both, in the end, are quality outfits.
to me on the 200tdi, I would do it again and again if I didn’t already have one.
in regards to manual controllers, I really need the adjustment To dial in EGT at altitude in order to max out performance. EGT’s/lean/rich is affected and although tuning the fuel screw is the proper way to dial that in, boost is a component. You can make the similar adjustments by lengthening/shortening the turbo actuator rod, but a dial is butter.
last comment is if you DO go the VNT turbo, an EGT gauge is a must, not a desire.