Is it possible to get more power with Dinan S3-R?

[Frankenstein M3]

As others pointed out you will need a new airbox over 6 to 6.5 PSI and at that point you mind as well get a different kit rather than try to reengineer your own kit. I only say that because if you do not get it dyno tuned you will run into some headache. Since you will change injectors, pulley, manifold, intercooler (basically a new kit).

[9kracing]

As others pointed out you will need a new airbox over 6 to 6.5 PSI

People always say this and it's simply not true.

The airbox is fine up to at least 10 PSI, and you'd be well over 500WHP by then.