need 2 stelling or imco extension boxes. Do anyone knows the difference on the two brands?? Neutral or 3"??

Stelling has a web site? Stelling Dealers?

I'd have to say the main difference between the two
is what they do for a drive shaft.

The IMCO uses a longer version of a standard
type merc drive shaft.

The Stellings uses a drive shaft with u-joints
on both ends ( to permit height adjustments)
with a intermediate bearing carrier.

which one is proven to be more reliable??
I have been told that the stellings are adjustable. by what means??

Check this site.
http://www.EverettPerformance.com


Mange

The IMCO has, basically, no moving pieces,
The Stellings, with it's drivehaft, has u-joints,
and a carrier bearing to maintain.

The inside plate of a Stellings has 3 sets of holes,
just like a outboard motor mounting bracket,
with it's multiple holes.