Dilemma over. This past weekend I bought a used 2013 LR4 to replace the LR3. Thankfully I found one with 13K miles and a CPO warranty. As much as I wanted to buy a new LR4, the SC6, eco stop, rotary shift and running boards weren't for me.
If I never drove a 2013, it would have been easy to go from an LR3 to a 2015 LR4. But every time I had a 2014 loaner LR4 while the LR3 was being repaired, I just knew that I liked our 2013 better.
Damn. Damn, damn, damn.

Just when I think I have finally made up my mind (after going back and forth a million times) for a replacement SCV6 for my NAV8, I read posts likes these I am back to the dilemma
Congrates on your find and purchase. Question for you though, would you have preferred TDV6 if it were offered here in the states? Keep in mind that the TDV6 has considerable low horse power even with that high 440 lb/ft torque I think. I wonder how the overall driving experience would have been compared to NAV8.
I just came back from a road trip to vegas, and parts of the highway 15 elevate has high as 4700 ft, so I certainly was making use of all those reduced-in-number due to elevation, remaining horses that were left to me.
I guess my dream motor for LR4 would be the TDV8 once offered in the Vogue trim of range rover in europe. This motor with 512 lb/ft of torque at only 1500 rpm would have been an absolute perfect match for this 6000 lb heavy and solid beast. But I think that engine may have been built by Ford so in terms of that buttery smoothness of the NAV8 (and SCV6 as well) that we all have been so spoiled by, I am not sure how it would compare to the NAV8/SCV6.
I can at least dream, right? Or maybe I'll call the SVO division and let them know that there are guys out there willing to "PAY" for such a version of LR4 if they ever built one. I bet if they built even 100 of those, they will get snagged up pretty damn quick (maybe time to start another thread.