Trade it for a Mustang? Or keep the Genny as a DD and go buy a real performance car as a weekend Mistress (what I did).
But seriously, maybe the subtle responses from my esteemed forum colleagues haven't sunk in.
The sad reality is that the Genesis BH just isn't an
aftermarket performance car. Unfortunately there just really isn't much available in the
aftermarket for performance
mods. Internal engine
mods have never been available. Years ago Garcia Factory in Korea made suspension parts.
KDM Motors Inc on FB was one way to get GF parts back in 2012 but they appear to be long gone. You can still get springs made at custom shops if you have a big wallet. Magnaflow makes catback exhausts for 09-12 4.6 cars, and there are gobs of wheels and brake kits.
If you want 400-500 HP then NOS is really the only solution available ... if you so desire. Sounds like you found a tuner. I don't think the engine internals in the non-turbo cars are forged ... and I'll tell you right now that the transmissions most certainly CANNOT handle that kind of power. But I guess you can find out the hard way if you wish.
The GENESIS STORE menu at the top is pretty much the entire performance
aftermarket for our cars in one convenient spot. Yeah sure you can ebay stuff too, but buying from
Sal helps support this excellent forum.

to the forum and please keep us informed of what you end up doing.