you can't swap pistons in the H22 without sleeving it because of something in the sleeves. . I'd say you'd prolly be better off getting one with low km's for a little more. The difference between the cost would hardly cover the cost of a stock rebuild (almost $1000 when its all said and done, nevermind the performance options you are considering)
Reliability wise, nobody makes reliability like Honda. Except maybe Toyota (hehe)