I wouldn't want to go down that road with the VQ. There's a couple of extensive threads here about that, but let's just say *if* it's even possible to reach 400+ whp on an NA 3.7, it would require a ton of time and money (basically replace virtually everything in the engine with aftermarket stuff, brand new heads from another engine, different exhaust cams, probably ditch VVEL and thus switch ECUs as well, etc... and then develop a few new parts). You're going against the nature of the engine going that route, and it'll fight you every step of the way. It's a losing battle.
It would be far cheaper (and much more turnkey) to do an SC or TT build targeting 450rwhp (rather than trying to shoot for 5-600, which is probably what ends up destroying some of them).
Or if you're really stuck on NA and you're willing to toss the ECU and stock dash (which again, a crazy VQ37 build would probably end up requiring anyways due to head changes), you'd get more power for far less money by doing an LSx conversion. It's been done before on the 350's, but I haven't seen a completed 370 yet. If (really, when) my engine dies from track use, I'm likely to explore that route myself, but we'll see when the time comes. If you're set on Nissan loyalty, a similar option would be to throw in the
VK56DE.