What does rxi and rsi stand for?

When the RSi corolla was first introduced it was aimed at the young boy racer market. The only standard option on the RSI was powersteering. Airconditioning was an option. TSA then realised that customers infact needed the bells and whistles and then fitted full leather seats , electric Windows and aircon was now standard. They then branded the full house version of the RSi as the RXi. Apart from that the cars are exactly the same. There is debate as to which is quicker off the line do the the extra weight disadvantage on the RXi Fareed