When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
"best" is a matter of opinion
I am looking at getting some custom tunes burned onto a TS chip.
I have considered Matt from gearhead,Tony wildman, Power Hungry Performance to name a few
Here is php's web link Power Hungry Performance - Available Products
Ask your question in the 99 to 03 diesel forum for additional feedback.
This is an awesome site,with tons of info.
Welcome to FTE. You'll only get minimal gains at best in the MPG department for the money you'll spend. As mentioned, look further down the main forum listing and find the 99 - 03 7.3 diesel section.
DP-Tuner and Tony Wildman are popular. PHP has become more popular lately, along with Matt at gearhead or even beans. Any of these will be 10 times better than the off the shelf stuff you see advertised everywhere, but you really need to install gauges, upgrade the intake and exhaust, and possibly install a shift kit and different wheel or housing on your turbo when you add real power.
The good news is, the 7.3 crowd can walk you through all this as a DIY project and keep you from wasting money on doing something wrong.