I have a W58 peanut on mine,, we put the engine together in the middle to late 90s for a 521,, that is no more, and i refreshed it and stuck it in my 510 a couple years ago,. I personally think it is a great upgrade, and hell, i use the single outlet exhaust,, because it was on it to be cheap. I don't only putter around town we make quite a few tears a month, down the freeway at 70-75 and it does it easily.
not tears as in secreting saline from eyes ,, tears as in hauling balls.