M103 300E engine swap compatability.

[Californian SE]

So the 300E has had a slight moment, and decided to shoot a piston out the side of the engine block. Lovely.

Down to business, am I best to stick with an M103, or should I upgrade the engine, or go for more economy while I'm at it? a 2.6 perhaps?

Although it would be easier to stick with the 3.0 M103, if anyone has swapped engines successfully I'd be interested in other options.
(And if anyone in Victoria by any chance has one for under 1K, which is the current price I have on one)
I only need the main block. My trans. injection etc is fine.

Cheers guys...