Claudius,
You don't NEED the APEX'i, orany other piggyback computer upgrades when you run a Motec!!! Motec is the best, its just that entry price is WAAY to prohibitive, and the tuning can take forever!!!
Gentlemen, you might also want to try the Apex'i POWER FC ECU upgrade. It costs about 1,300 US, but has all the adjustable features of the AFC (fuel control), AVC-R(boost control) and the ITC (ignition timing control). If you buy all the APEX'ui piggybacks, it will cost more than the POWER FC, which makes the POWER FC a sound investment, Plus, its 16 bit processor, so it drives smoother, and it has a base program which allows you to plug and play instantly. A budget Motec if you will. Drawback though is that it is car specific, not like a Motec which is universal.