You've kept that baby with great care, the car looks great Mash'Allah.
Well for headlights if they are just getting dull you can do a DIY (some very good videos on youtube, just search ek headlight restoration) and get them cleaned and they'll look just brand new. For the cracks nothing really you could do, you'll have to get a new set. If the cracks are minor, i'd suggest to keep these headlights as they are not visible (at least in the pic).
As mentioned Sultan you can get original stuff at Sultan ka Khoo. Will need to search a bit for a good piece though. Rs lights on stock, well this comes down to personal preference. I prefer stock over the RS in a light colored car.