[MrFlippant]

Are you talking about Technitoys' SCX Digital, also known as Scalextric the Digital System in Spain?
Or, are you talking about Horby's Scalextric Sport Digital, also know as SuperSlot Digital in Spain?
They are completely different and have VERY different installation requirements.

Hornby's Scalextric Digital is very much like Carrera, except that the LED needs to be on the center line of the car.
Technitoy's SCX Digital is a whole different kind of system, and chipping non-SCX cars is quite a modding challenge.

 

[MrFlippant]

The "Scalextric compatible" guide from Carrera is not small enough for R1s. Heck, I've seen that guide get stuck in regular turns if the joins create a narrower slot.
Best bet is to sand the sides down to make the whole thing thinner. If that doesn't do it, take off some length. Depth isn't a problem on Sport track, but if you have any Classic pieces, they might be problematic. It also couldn't hurt to make sure there's a little ramp on the leading edge of the bottom of the guide, to make sure it skips over anything on the bottom of the slot, rather than catch it.

 

[MrFlippant]

Ok, that's good. When you said "I will be converting a Powerslot, a SCX, a Carrera, and 2 Turmo's to SCX digital." I got worried.
Yes, SSD chipping is relatively easy.
As for the roof lights, what I did for my Carrera Charger police car was I wired the SSD chip and the head/tail lights to the braids, but the roof lights to the motor. That way, the roof lights are only on when the car is moving. That's what I wanted. If you want them on all the time, just wire them all to the braids. In this specific case, though, I kept the analog light board in the car, and took the power for the SSD chip off the motor outputs of the light chip. There was plenty of room inside the car body for the extra chip, since it had no interior.