i'm assuming they fit? the old mk1 1.8 8v models?

what is the difference between them and the 2.0 8v 440 lumps?

both manage to produce 110bhp, yet one with less cc

are the cams/ecu more aggressive on the renault version? if so, would the volvo 2.0 benefit from fitting an rsi cam and ecu? and what else helps it to that power?

I could of sworn the volvo engine made 115BHP. To be fair the renault was seen as a sporty hatch so it probably makes power at higher RPM as high RPM was not a thing volvo didon their cars. The bigg difference you will see is the torque. The 2.0 has a longer stroke to bore ratio making it produce more torque from lower RPM.
Adam

Autodata says 120BHP for the 4 series 2ltr