All checkboxes ticked!
The spark plug fits into fz25 bs6 model(bought in 2021) perfectly and delivers bit higher low end performance as expected. Although I don't see any considerable mileage improvements, I can definately feel the engine is running smoother.
Excellent quality.
Improvement needed in delivery time
Drag race between V4 Blue (Air filter & Free Flow exhaust) vs V4M (Only sparkplug changed everything else stock, heavier rider with 2kg crash guard) and it clearly shows the One with ₹830 upgrade (R15M) is faster than ₹4700 upgrade (R15 V4 Blue)... The V4 Blue even had a better launch than R15M, but the M caught up after 3rd gear
