If you have the certified GPS, then you don't need the ADF or DME. Just extra weight and added mx expense. I am an old timer, and I know I'll get a lot of flak for saying this. After flying a TON of GPS the past few years, I'll take the GPS anytime. BTW, I originally got my IFR in a 172 with one radio and VOR head. Intersection holds were a PITA.
