According to the QLD Transport Department the largest LEGAL donk for a 1200 ute is a 2.0L.
There are a few 2.0L donks out there but most (including me) go for the SR20. There is the FJ20, the RB20, Astron 2.0 or even the 2.0L series datto donks.
The reason I choose the SR20 is cause of the huge aftermarket performance support for them and they can also be STROKED easily (but not too cheaply) to 2.4L.
From a stock SR20DE I would be happy with 14's/15's down the quarter but the best thing is it can only get BETTER