The Frenchman warned that it will not be until the next week's final pre-season test at Barcelona that teams run in Melbourne specification.
Several rivals have commented on the pace of the Lotus, most recently Sauber driver Nico Hulkenberg, but the team is making no assumptions about its position in the competitive order.
"Confident, no, but happy, yes," said Boullier when asked by AUTOSPORT about his feelings on the car's performance.
"I know that next test everyone is going to bring a Melbourne spec, so we will see next weekend how it is going.
"Then you can stop to draw some conclusions. But the race is in Melbourne."
Boullier confirmed that his team will also introduce an upgrade package for the final test.
Lotus has shown glimpses of potentially frontrunning pace so far in testing.
It is expecting to make a good step with the Melbourne-spec parts and he does not expect other teams to make a significantly bigger step.
"After today, I hope nobody will find one-second of performance between now and then, it doesn't work like this," he said.
"It should be a reasonable upgrade."
Like all teams, Lotus has struggled with tyre degradation, with one of Romain Grosjean's race simulation stints cut short yesterday because of it.
But Boullier is reserving judgement until the cars run in warmer temperatures.
"It looks like they're degrading more," he said.
"But we saw last year when it was cold that the tyres were completely out of the [temperature] range, graining and degrading massively.
"We need to wait now to have hotter temperatures to see how the tyres are working and if there is a big difference."
"In Brazil [using 2013 development rubber in practice] the tyres weren't degradation that much."
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