im not willing to concede this one! Especially as all you have to do is google it! The SP may have come in single seat, but it then didn’t actually have OZ wheels, it had the basic wheels as Aprilia thought for superbike people would change them.
Take a look at the parts catalogue for the 1999 -2000 model, you will find a box with a solo subframe marked Mille R. The parts calague for 2001-02 has the same second subframe shown. By the time the 03 Mille R came out they dropped this feature. They also needed a small bracket to hold the tail fairing on the underside beacuse the standard bike used the longer subframe to bolt to. There is much confusion on may features of the various RSV 1000 because so many had parts switched about.
