hmm lets try and figure this out
piggybacks are : Fcon, E-Manage, usual EBC + SAFC combo and a few more im sure i missed
chipped ECU : badbiki, lumpyrom + many others on the market
each time u have new mod, you would need to retune your ECU on a dyno, depends on how much you want to spend. if you're looking for modest power levels then just an EBC + SAFC can be had for very cheap second hand which is what i would do
but thats just my personal preference