the peak of the torque curve is about 2500-2800 if i remember right. its not as low as a normal big diesel engine. these engines still have alot of gasser characteristics. they are based from a gasser.. and every properly timed 1.5 ive seen will get way better economy than the same 1.6 would. my grandpa used to get 50+ easy with his 1.5 engines, now he has a 1.6 in his caddy and struggles to get 40 out of it. my 1.5 also got quite a bit better economy than my 1.6td did. i would take a n/a fuel pump and swap in an 8mm eco diesel pump head in it. should use even less fuel yet that way.
another thing, 1.5's arent really hard to find parts for, unless something big and important breaks or goes wrong. like when you overboost your engine and crack the end off the block. lots of 1.5 and 1.6 parts are interchangeable.