I'm going to get made fun of and berated for this post and anyone that knows me can probably see where this is going but if you're willing to drop that kind of coin why not go for something that's awesome in other aspects as well as stupidly fast?
2011+ 550i's have 450hp twin turbo V8s that are over 500hp with a tune and instead of having a car that's fast in a straight line and compromises everywhere else you'd have an amazing all around car. You can get them for under 40k certified.
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I could be wrong, but I checked cars dot com and see nothing for 2011+ for under 40k.
And your numbers might be off too.
Im seeing 400hp 450ft tq.
The 2014 550i have 445hp.
Sorry just bored at work.