The glitch still works on 2.51. I've done it for all speed classes in SL, TT and Eliminator but never got it to work online. Once I could join an online phantom race on Syncopia though.
Moving the cursor back and forth after track selection seem to provoke the glitch to appear but you know, sometimes it takes 1 minute and sometimes 20 minutes.
To clarify you select Tech De Ra Reverse and quickly move the cursor up and down again before the screen changes to craft selection. Then press circle to go back and see if Tech De Ra Reverse has changed to Syncopia. The cursor must be in this spot because you can not move it to Syncopia when it appears. Repeat until success. If you are unlucky it appears but is locked. I don't know any solution to that but it rarely happens. Just keep on trying.