Ok here goes,
I have been tweaking my tec 3.3 for a while now and believe I have a very good base line setting. Its like I have a totally different car from when I first bought it.
Sorry traxxas but out of the box these things are great in a straight line but totally hopeless on the bends. However its a great chassis and can be sorted out to hang with almost any other car out there. (Oh and I have had some BIG crashes and its by far the most robust chassis I have ever driven as well).
Sadly you need to buy a few bits as follows :-
Ball diffs front and rear. Pricey I know but worth every penny and you can get them cheapish online.
Foam tyres or HPI belted. Sorry traxxas but the tyres its supplied with dont last and dont grip. I recommend foams because you get wider rear tyres they last for ages and provide the kind of grip you are dreaming of. I run on pretty bad surfaces and have never damaged one either.
If you can afford it the pro shocks are good but not a requirement for great handling.
So the setup. Fully tighten both diffs undo the front 1/8th of a turn and the rear 1/4 turn. Once installed they will feel a little notchy at first but will bed in. The front diff must feel tighter than the rear.
Put the rear shocks onto the lower inner holes and put a 5mm & 2mm spacer in. (One from largest size and next one down)
Put the front shocks onto the lower outer holes and put just the 5mm spacer in.
The car will be raked forward quite a bit and be pretty low at the front. Keep in mind that all though the front seems low at rest its totally different when driving due to the forces applied.
Thats all. Seriously I have been tweaking for a while and doing the above will give you a wicked handling car. Which for me is lucky cause I was getting fed up with it and was gonna sell it (lots of people taking the mic when they had a go was not helping). Now however the handling is sharp, the car is fast and everyone I know is jealous!