Mmmkay cera@1967, as far as I understand the main problem lays with the motor's inductive harmonics causing undue TRIAC triggering (mmm, sort of explains why the tool's sound was so nasty). Does this mean the BTA16 inside the box was overheating despite its relatively beefy heatsinking? 
The HILDA HLD-180W is also available at Banggood (with a lot of accessories I just do not need or want). It was there I saw this interesting user picture (the sort of stuff worth its weight in credits LoL!):
Another more powerful JD3321C version also available.
Cheers :-)
P.S.: no dust problems inside my tool, I cleaned up everything inside when I bypassed its internal SCR.