Noob question:  I'm trying to do a wideband conversion on my non-VVT 1.8T.  I have a 15 ohm 25W resistor connected to pin 115 (VVT output signal) of my ME7.5 ECU. Does the other side of the resistor just go to chassis ground, or does it connect to another pin of the ECU?

Next question: one tuner says I must have the VVT resistor installed or they can't tune the car, "it's required for adaptation". But another tuner says the VVT resistor is absolutely not needed, pin 115 can be left open, VVT can be tuned out. 
Which one is the right answer?
Thank you for any help.

Yeah, can be tuned out without resistors fine.  You should go with the second tuner as a start.