At least for engine management that's definitely doable, there are off-the-shelf ECUs for race/custom cars that are meant to be used like this (configurable via

At least for engine management that's definitely doable, there are off-the-shelf ECUs for race/custom cars that are meant to be used like this (configurable via USB so you can tune every parameter). For everything else you will most likely need to go custom but it's absolutely possible.