If you don't mind welding a new flange to your downpipe, I'd say a 16T with a flat flange is the easiest and cheapest way to go.
There are 2 varieties of the 16T, flat and angled flange.
For the flat flange, all you need to do is cut off the cone on your current downpipe and weld the flat flange on.
Advantage is that 16T's are easy and cheap to find.
I posted an ad in wanted a few years back and purchased one like a day or two later.
I don't remember exactly, but I want to say I paid somewhere in the $200-$250 region.
I have no experience with a 19T, but the 16T is a very nice upgrade to the 13C, I'm running it at about 0.9bar (about 13psi).
For spirited street driving and passing, it is more than plenty.
I'd suggest an Intercooler upgrade to go with a larger turbo, it was a night / day difference once I installed the KL Racing unit.
Thanks to everyone for the input.....I should probably clarify...
I actually have a T3 currently installed with a modified (silver soldered extension) drain pipe to work with a 90+ manifold running about 12PSI and a VAG CBV. (Barton turbo gage is the one without graduations so around 12PSI?) . (turbo rebuilt when I rebuilt the motor)
B230T was rebuilt about 14 years ago ( its a 94 block with squirters and larger rods, 2cd oversize pistons and now has about 85K kms on it.)
Has an M90 with a 3.31 LSD out of a 93 960 to give it long legs on the highway. ( I built it to do 4.0 hour trips twice a weekend when I was attending Staff College over a 12 month period back in 2007/8)
I have available in my stash:
- a16T flat flange turbo, a spare down pipe and I machined up a HD flat flange adapter on the lathe. ( also have an OEM flat flange stuck in my mailbox in NY but border is closed
)
- all the intercooler cooling and oil/H2O pipes for both T3s and TD04HLs variants for B230FT install.
- a 27 Row NPR I have never got around to installing...might look for it in the shed based upon the points above.
- a conical flange TD04 exhaust housing, but it seems to drag a little bit on the 16T turbine when I place the CHRA in it. (HL vs H?)
- a TD04HL-13T with an angled exhaust housing I pulled out of a 1999 V70XC over the past weekend (thought it was going to be a 15G before removing). Again the 16T CHRA/turbine seems to drag a little in the 13T angled housing...(Both are HL I thought??...is one a 6cm^2 and the other a 7cm^2?)
- a set of Fred chips I've never installed.
- a stock rebuilt 531 with 38mm exhaust valves and an IPD turbo cam sitting in a crate.
I don't mind a long drive. ( I used to drive a few times a year to my condo in Florida and put about 100K km on my wife's XC90 over three years in the Netherlands with lots of trips to Portugal, Spain, Italy..etc...) but these days I prejudice reliability and longevity to performance as I use this 91 780 as one of my two "old timer" daily drivers.
So..... I am considering just dumping the 16T into the car with the flat flange and modify my spare downpipe...easy peasy and hopefully reliable........or modifying the 13T I just picked up into a reliable 18T/19T in order to only have to do this mod once if feasible..... as life these days is really getting in the way of my car projects.......
Patrick