Hose in hose heated fuel line is great for heat exchanging and also it is easier to run under the car than huge bundled up Hose on Hose I have found. Biojake came up with this Hose in Hose using fittings from Lowe's and common sense.

We use 3/8 ID aluminum tube from McMaster.com. Industrial rubber hose from Industrial Rubber and Gasket in downtown nashville. We use 3/4 ID for the HIH and 5/8 ID for the coolant return from the tank. At the ends of the hose in hose Jake discovered that 1" X 1" X 3/4" PEX Brass T's work nicely. You simple solder a 1/2" X 1/4" copper reducing coupling into a 1" end of the Pex T. Then take your 3/8 drill bit and drill out the stops in the copper reducing coupling so the aluminum tube can pass through. The 3/4" ID hose fits very tightly onto the 1" Pex and is a royal pain to get on but it goes and you clamp it and it is on. The 5/8 ID goes perfectly on the 3/4" Pex. Here is a Pic of everything:

The heated tank can be one of the big ticket items. I spend about 200.00 on my tank, heater, hardware, and fuel guage. It starts with a Tempo below deck fuel tank from one of these online stores. They come in various sizes and shapes. They cost from 100.00 to 150.00. They have the fuel sender already bulit in. Here is a link to many at MarinePowerService.com where i got mine . I got the TP12SC. The plastic tanks insulate better, are easier to cut into and work with and are cheaper.

Blogging the A3 Jetta Conversion. We did this on a 98 and 99 A3 Jettas. Note: This system may not work good on this Direct Injection engine. After going 18,000 after an install and doing more reading trying to find success stories with a simple Hot WVO Fuel System in a TDI,  it may be that direct injection engines need new injectors for WVO. See here: http://journeytoforever.org/biodiesel_svo.html   Also , see my blog for running data of the system. I have the same system on my 2001 TDI. Nevertheless, this system is as good or better and several hundred cheaper any commercial heated fuel system such as greasecar and frybrid and I will give it its fair try on the TDIs. The worst that will happen is we will have to add Elsbett injectors and glow plugs. That would be one killer WVO system and if that does not work on a TDI than nothing will.