Good to be somewhat cautious about mixing kernels and ROMs. What I've found is that by reading the ROM developers web site (on Rootz, XDA, or ROM specific site) that they usually are really good about disclosing what kernels play well with ROMs. I've also noticed that community members are quick to point out issues or potential problems. The developers themselves are typically responsive and want to help, so if you have a specific technical concern then you could always ask.