Is there an r4 for dsi?

This is not a simple answer... let me explain: If you have updated your DSi to version 4.0 then you CANNOT because this update will have blocked cards such as R4 etc. If you HAVE NOT updated your DSi...

you can't. It just won't work with the newdsi the problem is that the dsi blocks anything that tries to bypass the main menu like an action replay, r4, m3 , tt and others (all don't work) the only...

any.

Because you need the r4i

I am inclined to say yes. Due to the fact that the DSI and the DSIXL are based on the same platform, do the same things, and operate in the same way. But you will need the R4I card.