This reminds me of the "I will not do your tech interview." post. [1]
There's a good chance if you're applying you're either a. unemployed, looking for a job, or b. you really want to work at stripe.
If you're passionate about what you do, you're going to enjoy designing anyways, so what better way to make you stand out than doing something that benefits the company you're applying for -- working on something you'd actually be working on.
Anyone can copy designs from dribbble to make themselves look like an amazing designer.
It's not like they're going to take your design, implement it and never reply to your email.
There is going to be some aspects of the design that can't be pixel perfect when it comes to a fully responsive site. This is because of the use of % based width to make the grid fluid.
If you're looking for pixel-perfect versions you're best off working with breakpoints and keeping the design rigid up until each breakpoint.
It's more work, but if you really want/need pixel-perfection then it's really the only way to go.