Finally i made a bold move today, change my 16k mileage T005A to Primacy 4. I can't stand the impact and road roar caused by the stiff sidewall of T005 and hope for calmer and softer ride from P4, and it doesn't dissapoint me.

I actually slightly up size my tyre profile from 215/55/R17 to 215/60/R17 in the process.

1. Low frequency road roar reduce drastically on those coarse tarmac, and i barely can feel those tiny vibration from the steering. The vibration is obvious in T005. With the same speed, now wind noise become very obvious due to the tyre roar is silenced. Previously the road feedback from road imperfection is too much, the steering vibrate as if the balancing is off.
2. The additional 1cm thicker and softer side wall absorb most of the impact when hit the badly paved uneven surface. The Impact noise transmit to the cabin now is very subtle especially go through those thick yellow speed line.
3. Before that T005 is inflated 210kpa during cold, now P4 at 220kpa yet still comfort than T005.
4. Didn't test the braking power as indon't think will be much worse than that. Cornering to me most or less same as T005, no big difference.
5. Tread noise wise T005 have the upper hand due to the fine groove used. U can hear it when ride through a very smooth road, u can hear slightly more mid high frequency noise from P4 but isn't a big deal, to me low freq road roar is the big issue.

So for those u would like to know user experience from T005 and P4 comparison, here it is.

more than 1 year? just 2 months only. So far so good for the 4k mileage that i covered.