I just de-customised the indicators and rear light. Previous owner had fitted the Tec LED unit and some long thin LED indicators. LEDs may be useful to reduce current draw when running a Joe Lucas dynamo, but all they do on a modern bike is push more undesigned current through the RR unit. A couple of weeks ago I led a run to Darley Moor racing circuit, and the lads following complained they couldn't see the indicators and brake light resulting in a near miss. I looked at a friend's new Yamaha Tracer indicators and they were pretty poor also.
As I didn't get the original kit with the bike, I had to buy replacements - an original RE light unit for £17 and a set of 4 ebay indicators for under £7. I bought a flasher relay as I thought I'd need one to suit incandescent bulbs, but wasted the money as the old LED indicators had electronic units on them that worked with the original flasher relay. I think all the lights are brighter in the daylight, and are visible from more angles than just straight on. Also the big rear lamp is more "Lucas shaped" and in keeping with the retro look I wanted in the first place.