I came across a honda j35a8 out of a 08 RL for a smokin deal. I bought it to have a spare motor. I currently have a j35a3 in the car now that is turbo.

My question is, will this motor work for me without having to do a bunch of mods to it? Will my ecu from my a3 work with the a8?

I noticed that the a8 has the single port heads, are these better than the 3 port heads? What is the CR on this motor?

TIA

is it a drive by wire motor?

yes

Completely different beast... You'll need a new trans adapter,exhaust,ecu, etcc..
The single port heads are said to be about a 15-20hp increase.
Compression is 10.5-1..
If it were me I would skip it and go to the J37.. or sell it for a turbo kit..
That MDX motor you have is begging for boost.

I actually already bought it. I couldnt pass up this deal. The ecu came with it also.

Will the a8 heads bolt up to my a3 block?

My car is already turboed. Im throwing a touch over 13lbs of boost at it. I'm very happy with it, but always could use a little more power.

I may consider selling it if its too much trouble to get it into my car.............

If I am not mistaken, yes they will but there is an issue with the cam gears and a oil drain-back hole. I think you have to put in a3-4 cams and sprockets but not exactly sure on that.
I am hearing the newer generation j35's are not taking as much boost as the older ones, one of the reasons being the cylinders are not straight metal and they will split.