Engine choices

[sofob0909]

Hey guys. I am looking for a new powerplant for my attex and surtrek. (Both the origional engines were locked).

I am looking at two different options and I wanted to see what yall thought.

Option 1

twin 400 JLO engines (~30hps)

I guessing the stock setup will be able to handle this fairly well without much beefing up

Option 2.

rotex 503 engines (50+ each)

Will the transmissions hold up to this?
What will need to be BEEFED up



My real question is what will I really get from the extra HP. top speed? more pulling power?

Thanks.