Having used both glow plug type heaters and the Vegtherm in my TDI, I think the Vegtherm is worth the extra cost, and it comes with a warranty. The GP heaters do collect burned veg. oil residue, you have to replace the glowplugs so the initial cost is short term, and if your system is plumbed in a way that allows petro. diesel or water (which shouldn't be in your fuel anyway) to come in contact with the glow plug (even in small amounts), the diesel will boil off creating a vapor lock in your system. The Vegtherm is well designed and tested, does not need to be maintained with new heating elements, can be used with diesel, veg. oil, biodiesel, and blends of all the above. My two cents.

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83' 240D 204,000 miles SVO conversion - Heated Pickup Stock Tank, 3 Gallon purge fuel tank, HOH, Coolant heated filter, FPHE, 2 Greasecar Valves. 12V pump for Veg. and stock pump for purge fuel. Injector overflow return to veg. tank.

98' VW TDI Jetta SVO Conversion 154,000 miles/57,000 WVO miles