Will +3 SC10 4x4 wheels put me wider than ROAR rules? All my wheels are DE +3mm. What is the max legal width?

The max legal width is 296mm. For 4x4 short course it is supposed to be measured at the axle centers but I haven't raced anywhere where that's been the case. Most places measure overall width (which can be affected by camber and toe angles) with a big gauge/cutout, or they place the truck in a box and see if it rolls out.
Either way I don't see the +3s being legal, even if you ran very little camber and toe.
That being said, unless you're running at an actual ROAR event, I wouldn't worry about it, just run the +3s.
Lastly, I'm assuming that all your tires are already glued to these +3 rims

This weekend I finally got to race my truck for the second time. I had the right tires, tried laying my rear shocks down, changed my anti-squat (flattened my arms) and the rear was still a little loose. (I noticed that, as someone posted, the rear was more loose off-power with flatter arms)

So I'll be changing my anti-squat back to how it was and lowering my center diff fluid. Do you think that putting 7k in it will be enough of a change? Or should I put 5k in it?

Regardless, I placed 5th in the a-main with this truck my 2nd time ever running this class. It was a pretty big memorial day race with 3 full heats of CORR truck and I beat some really talented drivers so, even though the truck isn't quite where I want it yet, it is still amazing and the steering and stability it has is incredible.

in general with the older vehicle when I had rear traction issues the thing that seemed to help the most was going lighter on the rear diff fluid. I was down to 2K at one point and liked it alot.

Removing the rear brace planted the rear end too.

Both my rear brace and center diff brace were removed as well.

What springs come stock on the 410.3?? What springs should I buy to have in the arsenal?

Stand your rear shocks back up (out on the tower) if you're loose in the rear. Laying them down is most likely what caused the loose off power feeling, not taking out antisquat. Less antisquat will give you more rear traction into a turn because it's allowing the suspension to be more effective through the turn. To exaggerate my point, imagine if you ran 90° of antisquat (arms vertical)- through a turn, the suspension wouldn't be able to compress and the car would just slide. This applies to accelerating in a straight line as well. With the arms vertical, the suspension can't compress and the car would do a wheelie if there was enough traction.

I wouldn't worry about this at all. Put the steering EPA back where you want it and let it rub a little. The original truck was like this as well and we didn't have any trouble with it. We wanted to maximize the strength of the arm which is why it's a little thick at that spot.

Sometimes luck overcomes skill. I only had one set of Blockades for both qualifiers and the main. They were well toasted after Q2. Good race, truck is still a little snap loose, but getting better and better.

I'm the pink/white truck.

+ YouTube Video

great race. that one was a lot of fun to watch.

From what I can find:

Slow blinking green is thermal. Red blink blink is low voltage.

http://www.hobbywing.com/uploadfiles...-09-SCTPRO.pdf

and the thermal can't be shutoff either. dumb. I understand from a warranty aspect why it can't be shutoff, but dang.

So what does remove rear brace really do on a low traction track i thought having the brace on to make it don't

Anyone successfully used proline body mounts on SCT410? If so, did you use the proline body posts or cutoff the top of the Tekno body posts? Just wondering. The angles on the proline mounts don't match the body angles.