After trying a few different parts, i found out some parts simply heats up and explodes faster than usual despite the stats are the same. The MK2 cockpit will always blow up first from reaching 900+m/s in atmosphere but after changing the head to Inline MK2 cockpit and the MK2 to 1.25m Adapter long can go up to 1500m/s without exploding at all. The Advance nosecone Type-A explodes at 900m/s while Aerodynamic nosecone does not. Many Winglet explodes but i found Delta Delux winglet can go further. I say many of the part stats are ether wrong somewhere or they have hidden and inconsistent stats which we do not know. Or a bug.