For anyone the most worthwhile upgrade is in driver education, most of us use only a fraction of the MINI’s potential.
Well executed head work is a great upgrade for beneath the bonnet. Gains can be realized at most rpm and load states, not just when the bypass valve closes. After that is when a header with larger flange ports and no pre-cat can work its best. Some improvement can be had since you’ve upped the boost but the cost/benefit ratio won’t be the same. If you decide to add a header, be sure to address the transition to the cat back so you don’t end up with a power robbing restriction. We’re getting off topic here (sorry MAFFA) but a less expensive alternative to an aftermarket header would be to remove the pre-cat on the OEM and if you get a ported head, the flange ports can be enlarged to match; that is unless the head’s exhaust ports are a mile wide.
