I'd go with Enya 53's with remote glows if you want seriously sweet sounding and plenty of power, but great throttle control.

A little pricey, but they last forever, and run like champs...a friend has one that was crashed, crank case broken open, JB weld used to put it back together, and still runs like new now.

And I don't know for sure but I think they make a deal to get the engine to run backwards, so your props spin counter to each other which is good news on a twin.