Recently conducted a test on one track (small mostly tight 90&180 degree turns). Compared the F104 X1 which I'd been racing there this year, F1ultra by exotek and f104 v2 pro.
Used the same servo, same motor & esc and rollout was the same across all 3 cars. Admittedly the motor was getting old as the x1 was competing between 1st and second but has dropped 3-4 tenths the last few weeks since the other fastest guy has pulled about 2-4 tenths on me since he got a new motor.
Night was very cold and there was dew on the track. Struggled with the x1 getting out of the corners as a result (normally not an issue). Car was decently competitive and despite losing a lap in an accident it put out 2nd or 3rd best time for the night (Was about 0.6 off the pace)
The f1ultra was brilliant. Really can give it some throttle out of the corners. Lacked a bit of turn in but that would have easily been rectified with some more toe out. Was 0.5 seconds faster than the x1. I imagine on a larger track it would have been even more as it could really make use of the width. Also took a bit of getting use to as it drives very different to the f104 x1.
The F104 V2 didn't have the most ideal run. I forgot to set the center shock so it was running too low and dragging the rear. Even still, it matched the f103's best lap times out of the box even while still lacking grip out of the corners compared to the f103.
Think once it is set up the f104 v2 and the exotek f1 ultra would be fairly even for pace. Just will depend on the track as to which would be 1-2 tenths faster.
Either way it is clear the x1 will be moving to the shelf now.