Cams doubt

[T_AE86]

One important thing i omitted (sorry), i know ITBs are very important to increase power in our 16v, but in my country ITBs are NOT homologable since 2012 january to road cars, TUV Inspection consider it like "competition parts", but i don't know why we can't homolotate ITBs in a 16v...but we can homologate swaping all engine to a 20v with ITBs (because this engine came with it originally)...legally we can homologate any swap with increases until 35% of original engine power (yes, we can't homologate only ITBs, but we can homologate a BEAMS saying it is a 160hp 3SGE)

Then, i want to consider how much money i'll spend to how many power will gain with reliability. I would prefer a 16 with ITBs and head worked, but without ITBs power gain is more limited...swaping to 20 i'll have this power gain in theory (i know about some 20v that are slackers in any forums). In the begining, i want only to take cams to an original head...but frineds make me think if is profitable to spend ~500€ for a bit power?? or is better to spend more to gain a good power increase

PD: i know too swaping to 20v implies manifold, air admision cleaner, radiator+fan, etc