what exactly do you gain with a box????does the boat act bigger?? can you run more aggresive X-dimension's?higher speeds ? better handling?

The drive sits further back off the boat. Therefore giving it more leverage when you trim, therefore, (in theory) picking the front of the boat out of water.

Atleast that's the way I understand it.

DAVE

Dyno,

From what I understand you are supposed
to gain a combination of 3 things, but not
all 3 depending on your boat.

1) Faster planning

2) Increased handling / leaverage.
Both in steering and trimming.

3) Speed

Good luck

Cougarman

I have the ITS from Merc on my boat. This integrates a 7" setback for the drive. The X-dimension was raised about 3" on my boat to compensate for the setback and it works great. The boat gets on plane fast so the higher x-dim didn't hurt anything there. I don't know if I get any extra top end speed with it or not, but it looks cool...

I agree with pretty much everything said regarding the boxes. Not sure if anyone mentioned this yet, but an extension box also artificially lengthens the boat thus it will react like a longer boat via the other bennefits as previously mentioned. It's probably the cheapest and best way to lengthen your boat without actually going out and buying a longer boat and even if you did buy a longer boat even that one would most likely bennefit from an extension box as well. my nickle

I thought an extension box put the prop into clean water which reduced slip. If you add a box to an existing hull you can change your X-dimmension with out modifying your hull. It also does give you more leverage when trimming but there are other ways you can get around that with out using an extension box.
Less drag and less slip equals more speed.

Im not sure on the "getting on plane faster" though. I was on a 26 Sonic this past weekend and it struggled a little to get up on plane. It got there fine but there was quite a bit of slipping, to the piont it sounded like it might blow out. The owner of the boat said you just have to stay on the throttle and it will come up. Sure enough it did but wasnt better than a non-box set-up. Anyone else experience this?

Tantrum

Correct, cleaner water, less slip more speed. Along with the rest mentioned.

We went with the neutral set back and the -2 IMCO SC's on the back of our non step 42 Fountain.
Can only say that the slip is at 8% and my fuel mileage is better.
It gets up out of the water with a bit less effort too.

Does Stellings have a web site?

DC, Unfortunately not.