Not too sure what forum your reading that says people aren't happy with Blouch? They are the number 1 selling stock frame turbo company for Subaru's. Maybe your mistaken with someone else, but Blouch uses Garrett CHRA's. For instance if you had a issue with your Tomei, good luck trying to get it warrantied in a timely fashion and find anyone who will service the actual turbo without having to ship it overseas. I mean don't get me wrong Tomei makes a good product, but for less money you can get a better product that's made in the US that has people that you can talk too on the phone that speak English. To be completely honest most of my customers end up replacing their ARMS turbo's with Blouch turbochargers when they take a shit.
Now going rotated, that's an option, but your starting to get into the territory of built engine again, a 30r isn't going to be a happy turbo until about 16 to 17 psi, that's when it's just starting to get into it's efficiency range. And when it comes to boost pressures psi isn't just psi, it's also the CFM the volume of air flow at that certain pressure can cause the same amount of stress on engine internals as 28 to 30 psi on a smaller stock frame turbo.
You came from a GTO which had that LS power instant torque and horsepower that you had available when someone would pull behind you and you wanted to say bye bye.
Sure you can have that in a Subaru, but a Subaru EJ series engine is never going to be able to take the abuse an LS engine could, not by a long shot.
It takes some dedication and work to build a Subaru engine to go fast in straight lines for highway pulls and 1/4 mile passes. Most Subaru owners keep the power level modest and focus on suspension because these cars were designed to be thrown around in the corners at a blistering pace. There are a small amount of STi's that I know of that hang in the 800 to 900 horsepower range. Fast straight like cars, but are absolute dogs in the corners. What most subie owners strive for is a all around package build, handling, power and daily driver readiness.
When you start getting into big power and rotated setups, reliability goes out the window. The rotated set ups also have a pretty big flaw and that is lag. The EJ series was designed for a small housing turbo, not a monster .82 or even .63 AR turbine housing. It's a dual cam 4 cylinder engine.
Put into the mind frame that your power goals are 400 whp and you want the reliability of a daily driver and having the ability to put your foot down anywhere and just pull from who ever gets next to you, I would not be surprised if IAG also tells you to consider building your short block. The pistons in these cars are the absolute weak link when it comes to making power.
I would honestly still consider going with a stock frame turbo that is relative in size to a 20g turbo and making what power you can safely on the stock engine, and enjoying that while you save for engine internal work, so you can march further toward your higher power goals while still having a reliable turn key automobile.
