Well, I was asked to post up some insight on why the turbo got sized the way it did, as I had a pretty big hand in helping them choose what they wanted.
The turbo is a T04E 60 trim cold side, on a T3 .63 a/r hot side. Initially I had suggested a 57 trim or even a 50 trim T04E, but I guess Keith talked them into the 60 later.
Anyway, Jim and Scott spent a good deal of time thinking about what they wanted to tune the car for, as in what sort of driving conditions. Ultimately, I think they made the right choices to meet thier needs. They decided that they didn't want to sacrifice normal usage performance too much for the occasional trip to excess boost, and that response/boost threshold was key to keeping the low compression 3.0L from being a dog during normal driving.
We spent a lot of time debating whether to go with the .63 or .82 T3 turbine housings, and ultimately it was decided to stick w/ the .63 for the response at the expense of some extra top end exhaust restriction on those occasional drag strip days. But this was also done with the understanding that if the .63 ends up being just too small for thier tastes, they can still go buy an .82 housing and put it on, or later on can have the turbine wheel clipped if they want something in between. Further, they are using a pretty nice wastegate, which allows some good flow, so that should help limit restriction at least some.
On the compressor side, I sized a 57 trim T04E to keep them in the peak efficiency range during normal "fun" driving (which will be the case for 90% of the time the car is under boost) and again, this was in trade off for some efficiency when running peak boost at the track.
Now, they ended up with a 60 trim, which really doesn't change things that much, except now they might have to tune around a little potential surging at high boost and relatively low engine speed. Should not be a problem at all with the boost controller they picked up. The trade-offs in compressor efficiency during high-rpm high-boost situations (at the track, boost cranked to 18psi or so) can also be somewhat corrected for by the use of ice or other "supercooling" media placed in the intercooler fluid reservior to increase the efficiency of the IC.
I guess the bottom line is that they didn't want the "beyondloadedSE" to be a dyno queen, they wanted a broad, useful powerband rather then squeeze every ounce of power out of it at the top end, at the expense of driveability and usefulness when they drive it on every nice day of the year.
