Im getting a new diff put in my BA XT this week, ive been thinking of going with a LSD convert plus gearing ratio 3.74. Im sure the xt is 3.32 stock.

What are peoples thoughts on the ratio? Has anybody done simmilar things?

you were close but the diff is a 3.23 gearing.
the 3.7 gears would be a good increase in off the line performance,(for a daily driver i would be tossing up between 3.7 or 3.9.. is this your daily?).
i recently blew my diff to peices so i also am looking to upgrade my ba xt diff...
my diff was previously a locked factory diff but im going to a set of 4.11s but it will of course be locked for fun....

Yeh its a daily driver. Ended up going 3.7 LSD.
Had to baby it for the first 400kms, but its absolutely effortless taking off compared to before!

Whats a general price range of getting a new diff installed on a BA?

ive just blown my diff in my ba xr8 for the second time , im going with the 3.7s, new lsd and half shafts, the gears set me back $870, half shafts are about $250 each

all up i think i was quoted $1850 fitted or $1350 if i pull the diff out myself and give it to them