I'm sure we'd be glad to help your cousin, but please ask him to define "best." Is he interested in performance at the expense of MPG and reliability, does he want to maximize MPG even if it means a marginal degradation in top-end performance, does he value torque over horsepower for say hill-climbing or towing ability, or does he value horsepower over torque because he's more interested in highway performance at speed? The question as you've asked it is so ill defined that all you're likely to get is opinion.