I am not really a fan of the Defi look But I think Tony's installation is really very good!

I remember from one of the shows last year (I think it was Nomads stand at the earlier Donno Spares day) they had a new carbon or plain fibre moulding that went along the top of the dash in the mk4. It had space fro three guages where TOny's are (on that flat bit of dash above the centre heater vents) and to keep it looking smooth it extended to cover the bit above the glove box aswell. It actually looked really good, and obviously the plain fibre version could be painted to match the dash.

If it was me I'd have three on one of those mouldings, then a "clocks" set up like Tony's (ACT + Stack RPM with digi speedo, but change the water temp to a boost guage like Jules said), and maybe one in the A piller if needed (boost, oil temp, oil pressure, water temp, might need another?)