Nope, no warranty, the car is a 2006.
Since both remotes have horrible range I think we have indeed identified the culprit as the tint or the antenna amplifier.
It's not a dealbreaker ...... I may not even pursue it any further, after all the remotes do still work - I just found it odd that the range was that much worse than my previous 2 cars, both E46's - one of those with tinted windows as well.
The word "there" can appear as a pronoun, as in “over there".
"Their" is a possessive pronoun. In a phrase like “Susan and Bill's car,” it could be used to to make a new phrase: “their car.”
”They're” is a contraction of “they are.”
“They are” should always be able to replace “they're.”
Extra credit: It's "I'm looking for an M3" not "I'm looking for a M3".