I run the Traxxas uppers and TLR lowers too. You can run Traxxas lowers, but the TLR lowers are taller and give you more adjustment.
I'm going to be running Avid springs on my T4 soon. I personally have not used Losi springs. I went strait from AE to Avid. But from all that I have read over the last 6 months, Losi springs didn't improve lap times in the trucks. Buggy guys liked them and they seemed to improve performance in buggies, not the trucks. So I stuck with AE till Avids came out.

Tires and shocks will be the biggest improvements.
Tires; ask around local track to find what works there.
Shocks; V2 shocks are good with the option of using Avid springs.
Chassis; no improvement can be had by buying a new one or any other.
ESC; for the money, brushlesshobbies.com is unbeatable for cost. I use one and its very good, in addition to my Novak which good for the money.
Motor; use what you prefer. All are good.
Servo; seems everyone uses Savox now. Should have no problems with either ESC brown outs.
I would recommend Avid Hex's as well.

Thanks man, say hi to Rickey Gaynor and Chuck Hicks from Mark if you see them. I used to race with them in Tucson

Anybody have any tips to help me improve rear traction on a dusty outdoor track? I've tried every tire I can find and still can't get the rear to stop wagging around like a dogs tail.

Whats your current setup? That helps in judging what will help.

softer rear springs and lighter rear oil. maybe try less antisquat to allow more rear weight transfer. It will not go through the bumps as well. A little toe in on the front might mellow it out too.

Right now I am using the gray rear springs, 27.5w rear oil, 2 degrees anti squat, -1 camber all around.Rear shocks mounted on inside hole on tower and on arm.

Front is blue springs, 30w oil, middle position on tower, outside on arms, no washers under front ball stud.

Ok, 3rd attempt to type this.....

Dusty tracks are going to be slippery. For me, I made my setups balanced and drove it loose. I removed some rear weight to help the keep control of the rear. You can do what markt311 suggested. You can try green springs in the rear and use the #1 shock piston if you aren't already. Your oil is low already so I wouldn't go lower unless the rest of the track will allow it. You can run 0 camber. Less camber will give you more side bite.

Ok thanks guys, heading to the track in about an hour. I am using the #1 piston. I'll drop the camber to 0* and try the green springs. If I have a chance may try the 1* of anti-squat as well.

.

I've never run the Avid springs, I've just been running the Losi BB springs on my B4.1 and my SC10. I like them a lot on both of my cars. What makes the Avid springs so much better?

The lap time improvement. Its posted in previous posts. http://www.rctech.net/forum/10830414-post114.html

Jbone, I believe your results and it's hard to argue with your success but I have to ask. How do you think the avids achieve this, after all it's a simpl
e component.

Is it the larger diameter prevents rubbing?

The lengths and rates are matched better?

They compress straighter?

They cost more? Just kidding.

Inquiring minds want to know.

Thanks

I am not gonna speak for Jason, but for me the Avid springs made my already good setup a little more consistant and more forgiving. Since switching to the Avids, the variable between my fast lap, average lap, and slower laps is much tighter. I can run lap after lap and stay within .200 of the last lap. If I land a little squirrely through a rhythm section, it doesnt upset the truck or ruin the section.

That's what I meant. The only problem I knew about the AE springs was that they rub the shock body, so if the Losi springs don't rub the body and neither do the Avid ones, what makes the Avid ones better than the Losi ones? I understand the lap times get improved, but why?