Is your reason to consider the 143 system to do with your available space? Or do you just prefer that scale? It might be worth considering Scalextric digital in 1:32 if you are just starting out, or Carrera 132 if you have lots of space. If you are already invested in some 143 cars then your biggest problem might be finding D143 lane changers, depending on where you live and postage options. Some D143 users swap to a D132 CU which has some added benefits, but will take quite a bit of dedication to wire into a D143 track depending on your level of electronics skill.
Small decoders are available, there is even a small, minimal parts diy option, (azya52 on github) it uses an 8 pin microcontroller and supports D143 functions but it all depends on your skill and time resources. I think the D143 system is restricted in the decoder firmware to reduce the PWM motor controller output to a certain level but you could probably fiddle with it to make it faster, or just use D132 compatible decoders to get the full PWM duty cycle and therefore, speed.
There are a number of aftermarket decoders available, I had ideas to introduce another, had some prototypes made, just never got around to following it through, maybe I'll try again but I can't say for certain at this stage.
