First of all, you'll get both items by disassembling junk at the assembly table.
For special parts, the regions you have to explore are Chalk Peak and Red Sands (Level 32 and 40+ required, respectively). Some of the zones that have the junk containing special parts are
Blackfell fallen zone
sunshine farm
Securement Silo
Rotten Saddle
Evergreen Vineyard
Kitches
Resedential areas
Some Items that yield special parts are:
CPUs
Coffee makers
Ovens
Bearings
Scrap Sniper Rifle Body
Scrap SMG Body
Welding Machine
For Refined parts
Explore the iron river region
or just do Securement Sio PSI run once. The parts that yeild refined parts are: