IMO, the H22 is old news and it's still overpriced.
Plus, you have to ditch the A/C to make it fit.
You can damn close to the H22's torque with a built B20.

And since I'm pissing people off, screw the B18C5...don't they still go for about $4000? :eh:

Here's what I'd do. Assuming CA smog legality isn't an issue...

1) Buy a knackered old B20Z long block.

2) Strip the motor down and upgrade to forged internals with a static compression of about 10.5 to 1. If 93 octane is available, you can go a bit higher. If you plan on using nitrous oxide, I'd go no further than 11:1.

3) Port & polish the head; reassemble with Crower 404s and the requisite retainers, springs and cam gears. Add an LS header, high flow cat and cat-back exhaust.

4) Reassemble, mate to a GSR transmission and install.
It'll drop into a DB8 with the stock mounts.

The stock LS ECU will work... but a programmable ECU will help. Add a dry nitrous oxide injection system, jetted for 75 hp ... add a few hours of dyno time and you're good to go.

You won't have a 8500 rpm redline, but you'll have a more useable powerband with more torque available at lower rpm. And with the nitrous oxide on hand, you'll have the top-end power to dominate when you need it. Furthermore, the bottom end is overbuilt to provide a safety net should you encounter detonation.