I started racing dirt track this year with an '89 Cavalier & its been a blast. I've learned a lot about driving in the dirt but I've come to the conclusion that my 2.0L OHV engine is too underpowered to the mostly 2.2L's I'm up against.

My question for any of you Cavy enthusiasts out there is how much trouble is it going to be to change to a '94 or newer 2.2L engine? From everything I've heard so far, the actual engine swap should be pretty straight forward. Will the newer engine fit into my '89 Cavy without any modifications?

Also I'm wondering if I'll have to swap ECU's & the main harness?

Yes, the 2.2L should fit no problems there.
You will need the PCM and wiring harness form the donor car. I would recommend either a '94 or '95. They come with the Hyraulic Roller cams and batch fire MPFI. Try for a '94 though, because of the Gen II body, the wiring harness will match the body perfectly.
What track do you race and do they have a web site with the rules? Might be able to set you up with a few more mods to help out.

heres my rules: PDF warning (not that big)
Hornet Rules

Im trying to figure out a setup for maximum traction and power within these parameters.

As long as I use GM produced parts its OK (factory production)

I have been planning on swapping beretta GTZ front and rear suspension (its still factory) I just dont know how to set it up. (stiff / soft, front / rear, more sway / less sway,)

i did that same swap on my race car 89 car but with a 93 engine. make sure you grab the later fuel pump, you will need that because the MPFI needs a higher fuel pressure.

Thats cool of a cavalier doing dirt track racing. I've thought about it but didn't really think I would stand a chance with all the STI out there.

Nevermind I was thinking about off road racing.