I doesn't matter whether the car is spec s or spec r, it matters which bumper it has. You can have either the standard bumper or the aero bumper regardless of 'Spec'. There are also numerous 'rare' optional front bumpers from the factory but i've yet to ever see one in the UK.
With regards to front lips, as has been said, an integra lip will fit but how much work is involved seems to vary depending on who you talk to, but they are in my opinion the best looking option available.
Others which were available include:
Two from Hasemi sport :
One from Jun:
A (quite nice IMO) option from ABFlug:
A Greddy option:
Aeroworkz Splitter
I have probably left out some more obscure ones which i'm yet to come across.