SU-30 SM has to be the best derivative of the SU-30 MKI. India's Sukhoi SU-30 MKI is definitely more advanced as compared to the Russian Sukhoi SU-30 SM.
Not necessarily true.
Su-30 MKI was actually a experimental project of Russia, quite a lot brand new technologies /aerodynamic designs were implemented for the first time. On the other hand, Su-30 SM was developed based on the experience of Su-30 MKI, especially those experience from actual operation. So, Su-30 SM is actually an upgraded version of Su-30 MKI. Regarding, material, structure and dynamic shape, fly control, it is better than Su-30 MKI.
Even in electronic part, we are not sure who is better. Those equipment on Indian jet must be better than those offered by Russians in hardware. But, remember there always is a gap between export version and self-use version. So, we don't know how much advantage those equipment has comparing to Russians' own version. On software side, it is purely a competition of accumulated experiences. In this part, no one is their match except Americans.