I have never heard about any problem with chinook as well. Guys, are you sure you want the discussion on which extension is better than the other one?
Btw, the statement in the first post..."they are the best...". How the hell you can say that, have you try all that you can get, or just 2 or 4 (even that is extremely lot).
I just think, get the one made by your sailproducer and you will not be far from ideal...from another suppliers i have experiance with chinook and the thing is doing just fine.