I'll just chime in and add that the non-5k GPs are very nice tires for the price. Got a set of 32mm TR's off ali this fall and rode them for around 500km.
You can definetly tell they are heftyer and feel a bit cheaper out the box than classic 5k's or P-zeros, but they were otherwise smooth, straight and hold air very well in a tubeless setup. Got a reliable feel to them and honestly not very noticable difference when riding, but i guess that depends on your level. If youre not racing seriously they're very decent value.
FWIW bicycle rolling resistance had them tested and found they rolled slightly worse than the top tier tires but oddly enough had amazing grip, especially in wet conditions.
