The h23a (blue top) is going to be a pain to find but I have seen several on ebay. Prices ranged anywhere from $3000-4500 and as far as any websites having it in stock good luck. Your best option is to frequently check on ebay and with some of the companies that directly import front clips and engines. A lot of the good stuff goes before the company even lists that they have it but you can put in a request with some of them (could take months though). F20b would require some customizing but possible. Compare all your options first. Good luck! I would be jealous if you did find a h23a .