Having deliberated with you chaps, I now have AMD's conversion of KO4's, new ex. manifolds, Milltek sports cats, etc and new clutch and cambelt while they were at it and 394.7 bhp (approx.!) and a rather lovely 424 lb/ft torque.

A fresh 4-wheel alignment was also carried out automatically where a seized TRE was replaced together with ANOTHER MAF!! That's 4 so far and 3 in 9 months. The 3rd one lasted a disappointing 84 miles before causing it to overboost and then go to limp mode.
Anyway, it is so smooth and torquey from 1500 rpm to the red in all gears that it's fabulous apart from being more of a risk to my licence and a huge C/c bill!

Anyone deliberating this conversion should go for it without doubt!!
HTH, Simon