where to get affordable ECM replacement
 

we're trying to buy a 1999 xc70 that seems well kept but is showing an ECM error code- and possibly is the source of somewhat sluggish acceleration
so we want ask all if someone , somewhere there exists an affordable place to buy and install an ECM; which Im told has to be downloaded with Volvo direct software into the car.
Any ideas please ?

It has to be an ECM that has no software already installs onto it. So a new one from the dealer.