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Hamilton believes McLaren will be "in the mix" for points come Sunday afternoon after the changes.
"Our car feels like it is an improvement from testing, which is a positive for us," said Hamilton.
"Whether we are as competitive as the others we will have to wait and see tomorrow, but I definitely feel we're in a position to get some points.
"If we were on the exhaust system we had in the last test then we would be in quite a lot of trouble, but today it was a big step forward, a massive improvement, a great job by the guys.
"The initial feeling is we're quick, although I'm certain the Red Bulls have more time within them, and maybe Ferrari too.
"Despite that we're in the mix, and some good points are on the cards this weekend. We are definitely on the right track."
Source: Planet-F1