You are not going to get much gains vs the £'s tou spend on a remap on the 3.0L, typical gains were ~10bhp.
Better investing in a performance air filter, (~£40'ish), and if you got loads of money a performance exhaust, (£650~£800'ish) and then a remap.
You also want to be careful putting more than 220bhp through FWD - this is normally the limit for most FWD cars.
I looked years ago, but could not justify a remap - assuming there is someone you can find to do it on a normally aspirated engine like the 3.0.