Jag V12 ECU Mods

[John Napoli]

A thread on another list describes the results of having a stock Jaguar
V12 ECU modified by an outfit in the UK.  The net of it is that very
significant performance improvements were realized.

The pros of this approach are that the outfit knows these ECUs inside and
out.  They obviously have a winning formula.  The cons are that their
service is somewhat pricy and maintainability is low (they are in the UK
and I am in the US).

An obvious question regards the feasibility of an ECU transplant with
something less expensive and more easily modified by local firms, or even
the owner.  

These engines have 12 cylinders and displace 5.3 liters.  They have one
injector for each intake port.  Could one not take a suitable ECU, say
from an 8 cylinder GM product, and work out a replacement?  Use the GM
sensors.  Somehow drive 12 injectors instead of 8.  Account for the net
difference in displacement.  Now you have a starting point.  How feasible
is it to fine tune from there?  Is this approach, overall, more risky or
more expensive than the option of paying a specialist for a modified
'stock' ECU?

I would like to hear the lists collective thoughts on this idea.

Thanks,

John