Hi M8,

1.

Yes you have to drop the tank to do replace the pump.

Just dropped mine.

It took me 2 hours.

I would expect a decnt mechinac with access to a lift could do it in under an hour.

2.

If your aiming for that sort of power i would look at something aftermarket, i'm not sure if these guys sell fuel rails for rev3's but take a look
www.wolfkatz.com
.

The standard rev 3 rail is meant to be quite good though, not sure it's good enough for 450hp? I would think for 450hp you would need an aftermarket fuel pressure regulator

(aeromotive etc).

If you fitted one of these you could fit the injectors and turn the base fuel pressure down until you got to the tuners and then they could tweak it

(this is what i will be doing with my rev2)

I think bhp is the factor when looking at fuel injectors.

You could have a massive turbo running 15psi and pushing loads of air into the engine, it would need as much fuel as a tiny turbo at 30psi for example.

HTH