Gday all,
          Just after some opinions and advice on what is a good budget LSD as a straight swap for the standard 2L escort diff centre. There are a few options out there but some are more expensive than others and may be overkill for a standard duty streetcar as this car will never see a racetrack! . Also some may be more tractable for everyday driving.
  Cheers for any advice
   Shep

There are no real cheap options.  The easiest is a TRAN-X plate type or Quaife ATB because they bolt straight into a standard centre but both will cost you around $1000.

If it's definitely only for the road then go for the Quaiffe ATB. Quiet, maintenance free and regular diff oil. If you think you may see track  use, even motorkhanas or hillclimbs & track days go the plate type eg tran-x, 3J plate type or Ford motorsport type Salisbury. All these require LSD oil.  Not much difference in prices and then you've got to figure in proper assembly.
rgds,
SFE 

*cough* welder *cough* 
but seriously i recently purchased a 3j plate lsd from smcka, $1050 and comes with all bearings, crush washer and new seal, although not cheap good value for money