Engine Health...What do you check?
 

So with me as of today having about 101000kms (~68k miles), I been hearing a few more rattles/noises from the engine. I somewhat suspect that they are normal, however I would like to be a bit proactive and check engine health.

So far I am thinking:

Compression Test
Leakdown Test

Are probably the 2 best ways, however is there anything else I can do to check? Rattles/Noises bother the SHIT outta me, however its hard to locate where they are coming from. For example, I have a rattle from 2000-2300rpm consistently. I personally think its a heatshield however 2 different mechanics (none of which were Mazda techs/mechanics): one said they think it was the heatshield, the other thought it could be something with the BSD. So it does somewhat worry me, but again I would rather do all my checking now so I can decide what needs to be fixed, changed out.

FYI Engine/Engine related Mods: CPe RMM, CPe CatBack Exhaust, Forge BPV v2, Piasini Tune/Reflash. (also have a short shifter, bushings, shift weight, COBB springs...however I dont think those relate to the rattling outside the car LOL).