Never figured it was worth buying a $100 machine and throwing $100 in parts at it to still have a mediocre machine at best.
Not when $179 will get you a machine that's got twice the power, DC output, and is gas-ready out of the box. (HF mig 170) I sprung for a Harbor Freight mig 180 a while back, mostly to have an el-cheapo machine that I can throw in my truck, and to a lesser extent, compare it against my blue machines. I ended up adding a cap, and replacing the factory stinger with a 10 footer from HTP, but it's definitely worth the money. It's no millermatic, but it's light years ahead of the flux core buzz box in every aspect.
When doing inductors and capacitors, you must design everything correctly, as you can get some weird electronic results as a result of the inductance/capacitance interaction.