I think Tugly has provided good advice. Make it run RIGHT, then make it run BETTER.

I have Aeroforce Interceptor Scangauges in my PSD's and seldom use the AE anymore. The best thing about this 'tool' is it is always there - no need for laptop, waiting for it to connect, etc... (this gauge will monitor everything AE does AND does buzz test, cyl. contribution test, etc) You can also add Fuel Pressure and Pyro to this gauge if ya didn't want lots of gauges.

For about the same $$$ as a 38R and bellowed up-pipes you can replace the limited options of the stock reverse-rotation turbo with a T4 system with an S366 turbo. (and ya don't have the obnoxiously LOUD 38R, which is a non-rebuildable turbo - aka disposable...)

I have AC code (160cc) injectors and wish I had gotten bigger nozzles. The advantage of single-shot injectors is being able to place the same amount of fuel in the combustion chamber in less time. Bigger nozzles just increase this advantage. With good tuning, this means even less smoke, lower EGT's, better MPG OR more power with the chip turned up.

I personally think FRx and HPx are very over-rated and just add complexity (and more chances to have a leak) without any measurable advantage. This is not a popular opinion - but I've found the more time and money people spend on something, the more they defend it and promote it...

I doubt you will see any gains from 'going thru the heads' - but if you really want to spend your money here, it won't hurt anything. Most people believe a 'seasoned' head gasket seal is better than a fresh set of head gaskets. The 910 springs only become an advantage with high levels of boost. Adding chromoly pushrods is also a good idea at this point. That said, these things are not that expensive and also won't hurt anything. Many believe anything over 40ish psi should upgrade springs and add head studs.

With 160cc injectors, 38R and GOOD tuning my truck makes 320HP in 'tow tune' and I struggle to push EGT's over 1200* - even towing at 24k bs GCVW. It makes 370HP in 'hot' tune and is pushing up to 35lbs of boost. Arguably, there is no need for 910 springs, etc with this set-up. Btw, this truck is an absolute BLAST to drive.

As far as IPR, they don't often 'go bad'. I'd get an upgraded HPOP (SRP1, T500, etc - let others debate what is better... ) and run the same IPR w/new seals. Same goes for ICP sensor, it either works or doesn't - if it ain't broke, don't fix it!

I predict with some extra power, you'll end up at BTS sooner than later. With some of the popular tooners - it may be MUCH sooner. Not surprisingly, of all the trucks I've been in, Brian's tunes make the transmission the smoothest and most predictable.

The point of a thread like this is to get opinions!! That's my $0.02!