What AN aluminum coupler adapter fits late m44 fuel rail?

[9G3Series]

Hi Guys, I'm thinking of complying the an aluminum coupler on the return port of the late m44 fuel rail, external fuel pressure regulator type, as the ebay listing here below http://cgi.ebay.co.uk/ws/eBayISAPI.d...ht_1567wt_1137



But, unfortunately, they don't have exactly kit for m44. According to my search, there are 2 types of the AN adapter, M and npt screw type. I am not sure which one and what size that gonna fit late m44 fuel rail though?

Here the link for M straight adaptor: http://stores.ebay.com/autofittings/..._sid=563989697

npt straight adaptor: http://stores.ebay.com/autofittings/...3989697&_rdc=1

Any idea?

Thanx a lot in adv,
-George