basically all tuners cars got nerfed by rockstar by adding advanced handling flags that cause this. i heard they can be disabled by servers not sure how accurate that is
Details of the Nerf
Top Speed Reduction: The primary impact was a substantial reduction in the top speed of nearly all 17 Tuner cars. Cars like the Calico GTF and Comet S2,
Handling File Updates: Rockstar introduced specific "Advanced Handling Flags" into the game code for these vehicles.
Impact on Drifting and Acceleration: The handling changes negatively impacted the cars' acceleration and disabled the "double-clutching" or "Mid Drive Speed Boost" technique that players used to initiate drifts and gain speed, making them much harder to drift properly.
Engine Sound Glitch: After the update, the cars also developed an audio issue where the engine sounds like it is trying to shift gears at top speed but cannot, a side effect of the speed cap.
