I came from a 500 hp E55 AMG and I do not miss driving it one darn bit. I went with a 70D Model S. Would a P85D be awesome? Of course - but I needed to get two Teslas so I had to save somewhere by going lower spec.
Having said that - what are your plans? Do you plan to keep this car 500,000 miles and 10-15 years? If so you perhaps might want the larger battery because when your 60 degrades to maybe 80% of its capacity 200,000 miles from now you won't have as much excess to start with. OTOH 60's now have 75 battery packs so you could always pay later to upgrade it.
And, the $18,000 you save would probably buy a much larger replacement battery pack 5-8 years from now if you decide to keep the car forever.