My thoughts too, you'll get better power and more DIY tunability on a budget with a TD lump from the get go... our TD swapped 206 is still on a K14 turbo/22psi currently (estimate 180+bhp) with mild pump mods and mated to a GTi180 flywheel/clutch and GTi gearbox it's mental & the engine picks up revs so much better with the lighter flywheel while still being plenty torquey enough. (only thing with the GTi 'box though is you're quite high in the rev range at 70mph, not that the derv won't rev 6k+ but it's loud at motorway speeds. If we were regularly on dual carriageways/m-ways I'd go to a longer legged DT 'box).
Saying that, given the limitations of the ECU and high compression engine I think low-blow supercharging might be a worthwhile avenue to look at with the 16v lump. It'd give a nice boost in torque at low revs with no lag & a worthwhile increase through the rev range, but not really a project for newbies as it'd take either solid working knowledge of the engine/ECU as a whole OR my preferred method of just enough knowledge to be dangerous mixed with a little research and semi-educated guesswork & risk-taking on part selection. (We've been sort-of considering a blower on the 180, although not seriously enough to have any helpful info on that route yet, just the idea in my head and the theory that it'll work well)
Saying that, given the limitations of the ECU and high compression engine I think low-blow supercharging might be a worthwhile avenue to look at with the 16v lump. It'd give a nice boost in torque at low revs with no lag & a worthwhile increase through the rev range, but not really a project for newbies as it'd take either solid working knowledge of the engine/ECU as a whole OR my preferred method of just enough knowledge to be dangerous mixed with a little research and semi-educated guesswork & risk-taking on part selection. (We've been sort-of considering a blower on the 180, although not seriously enough to have any helpful info on that route yet, just the idea in my head and the theory that it'll work well)