Cars come along nice, i don't see why the dyno shop would say its off 10hp or tq or whatever.
Good friend of mine has had a X for a while. I'll share the videos of the setups he has gone through.
Stock longblock, & cams, dom 2.0 turbo and meth:
http://www.youtube.com/watch?v=MhIyUdfVnnY
Buschur built block full supporting mods and FP black setup:
http://www.youtube.com/watch?v=D1K8suy5T8k
The dom 2.0 setup was good, he went mid 11 consistently with it (w/o really trying), drove great on the street and had room to improve. The room to improve is what ultimately killed the stock motor though. Between upgrading the head/cams, rod bolts, and multiple other small things, and a bad tune the motor blew apart. I wouldn't reccomend installing arp rod bolts on stock rods, and i'd pick your tuner wisely.
The black setup is just awesome. Obviously a good bit of money was spent but after the carnage of the stock motor so many new things needed to be purchased that the buschur block made sense. This car also had one of the first fp blacks on it and JMF tubular exhaust manifolds. Once having a good tuner handle it (peteyturbo @ krazyhouse customs) the X was just a beast. I've been in cars a lot faster then it, but for what it was (weight, gearing, 19s etc) it was moving. Sadly it never got good passes down the track. Realized that with 19's, and the stock drivetrain/gearing of the X it was going to be a lot more tricky to finally crack 10's. He hasn't been able to get it back to the track on stock wheel/tire size but he'd gain a bunch rite there. I really feel like the black setup on the car is the way to go. If your going for all out 600+ HP then obviously a T3 frame bigger turbo setup will be best but for day in day out with good power potential the black is the turbo to go with. I also feel like it would be great for road course tracking if that was you thing as well. Spool up is great, sound of it is like a big turbo, and for a stock frame housing it made good power.
I'd grab 1000cc injectors at least, arp headstuds (not rod bolts tho), upgraded fuel pump, and figure out the best clutch setup to hold the power comfortably.