Neutral balance is much easier on parts, IE: less bearing wear. It is the choice for high rpm engines. External is easier for the OEM's due to machining cost. An external can be converted to internal but the cost varies depending on how many slugs of mallory the crank takes. You can figure labor and cost of metal at around $75 for each piece installed plus the balance. Street motor, save your money. Competition engine, spend the money.
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