Hi Darryl,
i have had a good look into this and spoken to the vro and have the following to offer.
VRT and the cars road tax rate is based on the co2 rate of the engine of your donor car.
Any Sierra petrol (if you can get any official figure from ford) will have you in the 32-36% vrt band (not a problem itself) but locks the car to €1100 or €2100 a year for tax for life
you need economy of 45 mpg petrol, or 55 mpg diesel to get sensible tax rates so
A 2001 fiesta tddi e-diesel has a co2 figure of 120 gCO2/km which is where you want to be for €104 tax and 14% vrt.
(I'm sure someone can confirm if this bolts to the Type 9 or MT75??)
from revenue.ie
" This is the level that will be used for taxation purposes and will not change regardless of post-production modifications that might be made, modifications that might either increase or decrease the levels of emissions of the vehicle"
which means you can fit the diesel for registration then do what you like!!
