When you're making more than 300 pounds of torque, the primary concern is the transmission pressure plate. Cheuk has conveyed that almost nobody wants to redesign the pressure plate (aftermarket-speaking) so the ONLY way to get around this is to use a multi-disk clutch like an HKS twin plate. These are expensive as hell and aren't very streetable...
The differential will not live through that abuse either; you'll have to go through Quaife or Kaaz for a replacement. Kaaz works on a clutched limited slip, whereas Quaife works on an autobiasing gear-driven limited slip. The Quaife has a much longer service life and better power handling. The prices are basically the same, so I suggest the Quaife.
The rods are easy, call up Crower and ask for a set -- they're $675 including shipping and you'll never break one (I think the rating is 600lb/ft at 8000 RPM's, which is like 914 horsepower) However that leaves another problem: if I remember correctly, the Ballistics pistons use their own press-fit pin (in order to work correctly with the stock rod pin bushings) Unfortunately Crower uses a floating pin bushing in their rods, which means you will need different pins for your pistons. You will have to ask UFB how to resolve that issue.
There are also fluid- and thermo-dynamics issues involved with that much power. Making 400+ horsepower means you're going to have a HUGE pressure buildup in the exhaust manifold if it isn't designed properly. Unless UFB is providing 40+mm external wastegates and a nice tubular manifold (not a log-style) then you're going to get nasty boost-creep problems and heat-soak problems. This could potentially lead to detonation and actually LESS power because the exhaust gasses will be unwilling to evacuate the cylinders. It can also cause premature failure of the manifold, the turbo, exhaust valves, exhaust valve guides and piston rings.
A lot of planning has to go into a buildup with that kind of power, most of it "Mr. Normal Joe Blow" didn't even know about. That's at least one of the reasons I threw the 'technical foul' flag on the UFB kit to begin with.
-Red-