If you want to go for the Dummy(artificial) tips ,its very easy..........You remove the plastic covers on either side and weld on your favourite tips directly to the silencer....easy........................!Now you have the look with the engine stopped.
Once you start it up ,you will have smoke coming out of the bottom of the car and your dummy tips will always be clean.So,it will be a good idea to paint them black on the inside to give them a more realistic look!