My own TT-01 Rally Mod
This is a Tamiya TT-01 (E) rally mod using only stock parts. I tried to limit cutting into pieces as much as possible. Only the reinforcements on the cups were compromised.
The basic idea is to extend ride height. You'll notice that you can lower the arms as long as you have the bumpers connected. You can either cut the bodem plates so that the arms have more room or you can simply remove the bumpers. Best option is to make some new bumpers when you create a protective (plexi?) bodem plate.
To lower the wheels you need to change the mounting point of the shocks. You can create some adapter to be mounted on the shock towers, you can get yourself longer shocks or you can find a mounting point on the existing towers. I ended up tie wrapping mine in place just below the shock towers. Not ideal but working so far and very cheap.
And finally you'll notice that now the cups on the back are striking against the arms while driving. The cups have some reinforcment knobs on top. You can sand them off using a dremel tool. That's the only cutting I couldn't avoid so far.
Don't forget the rally block tires! These do provide better traction but you'll also have more dirt flying around (and in your car). The internals of you car are already pretty well protected. If you want to keep all dirt out of it you can always create an inner shell.
Other Resources for tt-01 Rally conversion
A great idea I found on the web is people modding their TT-01 for rally use. This is basically what you'll need to do to get the desired ground clearance. I'll list them with a clear picture.
1) Mod low bumper holders (front and read) by removing some material so the A-arms get more travel.
2) replace the stock shocks with slightly larger, adjustable and oil filled shocks. These are available on ebay for around 25 EUR.
3) Make an inner polycarbonate shell (like the HPI RS4) to protect the electronics. The TT-01E chassis is already better protected but you're best option is to close the wheel sections as good as possible.
4) Install a brushless motor system upgrade. Not really needed but it gives you more power which is always nice.
5) Add dirt tires. That is really necessary yes
6) Check that you have around 1 cm ground clearance.
And this is a link to a topic that's all about RC Rally racing with tt-01 chassis. And check this website for nice RC Rally car pictures.