I've colored my natural hair with a permanent color before on a couple of occasions. The first time my hair was at least near bra length--I believe. I colored it a honey blond using Dark & Lovely if i remember correctly. Back then I didn't as much as I know now about my natural hair now. I didn't lose any hair but the cuticle of my hair did swell up. So my hair was thicker and I'm sure a bit more porous (although my hair is normally porous anyway) The second time my hair was colored was with golden blond and golden brown highlights. These were done professionally. I think highlights are much safer than all over color. The damage--if any-is minimal. Depending on how you choose to style you hair-- a permanent color should not cause havoc IMO. If I was smarter I would have deep conditioned on a regular basis...
I've done rinses too! I LOVE rinses but you'll never be able to lighten you hair with one. They created rich deep colors on your hair with a lot of pure shine.
I used to get rinses made by Matrix but they've been discontinued. This fall I plan on applying a Sebastians colourshine. The best thing about about a rinse is that it coats your hair. It protects it and makes it look thicker and healthier IMO. But the downside is that they wash out after so many washes. That's why I'm waiting until the fall to apply one. I wash my hair too often to hold one for a month right now.
Hope this helps...