Upgrading to a FMIC from a SMIC on an otherwise standard car will give you very little advantage and will probably cost you £150-£200. A phase 1 remap to 165-170 bhp will make a really big difference and not cost much more. If you were planning on doing more then this a FMIC may be worth it.
The FMIC really gives you more consistent power especially in the summer. Quite often they appear to give really good gains on the dyno because the cooling fans usually dont cool as well as they would on the road so the intercooler upgrade can appear to give you more on a dyno that it would on the road.
Karl.