"We were pleasantly surprised at the number of people that have enthusiasm for these cars and that are willing to put down the extra money to get into an electric vehicle," he said.
"That means the Gen 3 vehicle is most likely a much-higher volume vehicle than we were previously considering, and that means that the longer-term earnings for Tesla will be significantly higher than where we previously thought."
(Read more: Congress needs 'a violent move' in market: Dick Bove)
Irwin added that Tesla's drivetrain had achieved cost parity with other comparable vehicles, which could lead to lower costs by 2015.
"In that case, why would there be a premium? So, really, it would be the enthusiasm of the buyers in the market to buy these vehicles—possibly for the same price, maybe for a better price—that would really be the longer-term buyer, longer-term driver," he said.
(Read more: Tesla's golden spike: Coast to coast, no gas)
Irwin, who said that his background was in battery technology, also noted Tesla's advantage in this area.
"I've not seen a competitor that has a cost structure on their battery that will approach what Tesla has," he said. "That means they will be fundamentally higher priced and less competitive with the products that they bring to market.
"For example, I really like the BMW i3. It's getting some good orders. It will see decent traction. But I'm skeptical that the price point that they're going to be selling this at, that they're going to make anything close to the amount of money that Tesla makes on the vehicles that they launch," he said.
(Read more: Bears to get 'killed' in October: Josh Brown)
"If they can cut the cost of their battery in half, then we've got a winner, and that's why I'm upgrading it."
—By CNBC's Bruno J. Navarro. Follow him on Twitter