R&D Expense--when to remove?

I have a suspicion that in an era of high or --P/Es, we can justify 'some' values by excluding R&D for R&D-specific companies, when a 'valuation' has to be forced

THink of Tesla--sells 1/1000th of the # of cars Ford or Toyota do but is worth more by stock valuations. For years they had negative operating income

If you had to say "this value $ leads to this terminal value" would it be OK to exclude research & development expenses from Operating Expenses?

I understand that's sort of a stretch and this may fluster some academics/good guys but what else should someone do to make a value on a stock where Expense is almost as great or GREATER THAN Gross Margins? :P

Appreciated