It’s impossible to evaluate a deal like this based on monthly payment and drive-off alone. You’ll need to know the inputs that went into the lease – MSRP, selling price, residual value, money factor, and incentives – to see how much room there is left on the table.
What I suggest is to first calculate your ideal lease for this car. Create a target deal for yourself. Know in advance what kind of deal you should be shooting for. Then, compare your target deal with the offers you receive.
To calculate your own lease, first research the relevant info. Google “edmunds 3-series lease residual” and you get this page, where we learn the lease rates and incentives for 2021 M340xi are as follows:
36/12
.00082 and 57%
$1500 lease credit
Enter these inputs into the Leasehackr calculator: CALCULATOR | LEASEHACKR
I assumed a selling price of 8% off MSRP. Aggressive discounts on BMWs generally range from 8% to 10% off, depending on the model and region. I didn’t include any incentives other than the $1,500 lease credit that everybody gets. (There are usually additional incentives for Loyalty, College Grad, Conquest, USAA, OL Code, etc. Look them up.) You didn’t specify your location, so I left government fees, dealer fees, and sales tax as the default variables.
Looking at the outputs of that calculator, and comparing it with the offer you received, it seems like there’s a lot of room left on the table. Feel free to adjust the inputs of the calculator accordingly to match your needs and circumstances.