The DOHC ECU will not do ANY harm to your SOHC. It runs the engine a little richer (rich=safe, lean=kaboom), so with mods it should increase your power considerably compared to the SOHC ECU. If you think about it since the DOHC ECU is adding more fuel, if you do mods to increase airflow it should be a lot better for making power.

 

i thought if the car was running 2 rich it could blow the piston rings?

 

if it runs badly rich the extra fuel washes the oil out of the cylinders, just a hair rich dont hurt a thing but the guys nose behind you

 

i do not want to blow my pistons so i dont think im going to do that...

 

It won't hurt the engine to run it. I know people who do. You may need to change your plugs more often though.

 

oohhh!

would it add a considerable amount of power?

and which plugs?!?!?!?!?

and how often?

 

Might not be noticable...
Your spark plugs and maybe every 5000 miles or so.