Trying to cut down costs makes it harder to see. I think it is easier to compare with other large volume cars. I think its a pretty close comparison to say
$ ICE Components = $ EV Components - $ Battery
So for now an EV will cost roughly the battery pack more than an equivalent ICE. From the rough estimates we've seen for battery costs I assume the model 3 battery pack will be ~$10k.
So the base model 3 will be the equivalent to $25k ICE cars in rough quality of interior and finish.
But on top of these we have a few extra things going for the Model 3:
- EVs with large batteries have inherent higher performance potential
- Skateboard allows more radical design
- Skateboard allows more available volume (storage/passenger)
- Skateboard has low center of gravity for better handling
- Good designer who isn't trying to protect other model lines with crappier design
- Mostly electronic controls gives more features for same money
- Trickle down tech from S and X (versus legacy components from other cheap cars)
So as you can guess from my thoughts above, I think we'll see a pretty compelling car for $35k. But parts that aren't inherently superior in EV will add equivalent costs in options (leather, paint, sound, trim, sun roof, wheels)