Im not the best person to ask, Stu is, as i dont know about all the different L1/L6/L8 etc and what the options are on each.

But certainly there are retard wires in the loom, that can be confgured as part of the remap and then when grounded (think its grounded anyway from memory, Stu can clarify no doubt!) tehy take off a fixed amount of advance, ie 1, 2 ,4 degrees or whatever they have been mapped for.

This is a feature oringally on the ECU for in applications other than on the cossie as far as i know (dont forget these ecus get used in loads of places), rather than specically on the cossie, but its very useful potentially for either big doses of gas, or running different fuel types.