The drift model of the RS4, IIRC, uses a different chassis plate and a central mounted engine to move the weight forward for drifting. You'll most likely never get it to handle as good as a regular touring car, but if you're just bashing you can probably tune the chassis a bit with shock oils, springs, tire compounds, et al.
HPI even had a conversion kit for regular nitro RS4 Evos, but that had a different header to reuse the stock plastic pipe. Note your RS4 3 Drift is also single speed. The conversion kit kept the stock two-speed.
You might be able to get a new chassis plate online somewhere (even here in the classifieds) and transfer most of your gear and then you can upgrade whatever you need to go back to a normal TC layout.
HTH...
Mark