I would add up the likely total cost first if I were you, as no aftermarket ecu and set up will leave you with a small bill!!
The std ecu if adjusted/mapped right if possible will do the job just as well.
I would forget about closed loop, if it mapped correctly it is not needed.
If you intend to do more mods such as cams/tb's/turbo etc down the line then a good approach if you can afford it is to get everything done, then set up, as otherwise it will need a new set up with any major change.
Aftermarket ecu's tend to be much more useful in tuning as unless someone has the identical chip for the mods you want you are stuck.
tabetha