What is the difference between the raq4i and the raq4r ?

When i install a second drive in my raq4i server with
the raq 4r iso file, is it a raq 4r with raid option ?

I am pretty sure you are correct. If you get another hard drive for the raq 4i and restore the raq with the 4r iso, I believe it will work. I've never made a 4r out of a 4i, but I've made a 4i out of a 4r by taking a hard drive out. I'm pretty sure it has all the same hd, and IDE raid stuff. If I were you, I'd try it out, and if it doesnt work, just change it back to the 4i.