OTOH, my rough calculations are, if you could do it in as little as $5,000, which would be the low end, let's say you're a great fabricator and did it all on your own, you don't count your time, just parts ....your payback could be as little as a year, if you drive a lot of miles. You could have weeks of labor into it too, and countless troubleshooting hours.
There's got to be a good number of Eco Diesel 4th gen's down in Tx... Might be time to look for a new (used) 4th gen. Couple downfalls on the Eco Diesel's: 1) Fuel costs a lot more per gal, 2) Not all shops work on diesel's, 3) There's DEF costs. 4) They're louder, noisier, vibrate more and smell up the garage (if they aren't running in tune). Other than that, they're cool.