Ok bro dont bother wasting your time and money in putting in a xr 6 engine, I know of several EB 2 4L that were running low 14sec quarters with over 130 kwrws.
by the way how many kms has the engine done it might play a part.
FIRST Throw in a unichip.
SECOND I suggest you put a a mandrel 2.5inch exhaust system there a quite a few out there so do your homework, and also a hiflow cat 2.5inch, this may cost you between $500-$1000.
THIRD if its auto, I suggest better gears in the diff, I would go the 3.9lsd I am saying this because of the 4 speed I believe at 110 kms they will rev at 3000 to 3500, but the advantage is off the line, I have seen a .5 sec drop in a auto xr with a 3.9lsd fitted with no probs reving on the highway because of the 4 speed, but if its manual I suggest 3.45 gears.
FOURTH Cam and head work.
With all this done you should make over the 130rwkw mark
One of my friends made 142rwks out of a 4L cost around $2000
For that price thats excellent.
Ran a 14.2@95mph but manual 3.45
IF YOU DONT TRY IT YOU WONT KNOW.