$1k a month? Naah.
128's will probably lease for $299/mo, 135's $399. Just guessing based upon 3er leases. Whatever the figure is, it won't be that high, I'm guessing the 128 will be the new BMW value leader.
A buy should be between about $550/mo for a 128 and maybe $620/mo. for a 135. And that's without money down.
If you're paying more than $100 a month in insurance, shop around or move.
I'm not in that young-ish bracket anymore, and I certainly didn't make enough to afford a ~30k car at <25 years of age... But there's a lot of folks who will be able to afford this one.