The price for that 160k is horrifying though, esp. if the requirement is bursty rather than continuous.
But yes, it's pricy. It may not be the best fit for some. Hopefully by the time you're taking 160k writes per second you have a solid business model. I mean, Twitter peaked at around 8000 tweets per second. What are you doing that requires 160k, and do you really need to be storing it?
For example by changing my query strategy I was able reduce the provisioned write units from 1900 to 150 (write units dominate the cost).
Sure, you likely have more than one table on RDS, so that cost is amortized, but when you get to the scale where you need 160k reads/s, you aren't going to have much more than that one dataset in a single instance.