Nelson is kind of the big name in South Texas, and come highly recommended by a lot of people. I eventually plan on going somewhere here too. I may go with Nelson, but I called them about a tune a while back, and they told me for the Efan mod, I couldn't use the factory harness I pulled, and I needed a custom e-fan harness (that they could sell to me) because my pickup is an 02. I know its only an extra relay to switch polarity, and it put a real bad taste in my mouth.

I recently found this.
LSX Performance by 360 Automotive - Auto Repair Shop in San Antonio (business.site)

They also have a facebook page where they promote their ability to do LS swaps in all sorts of vehicles, and do dyno tuning. I know nothing about them other than what I have seen on the websites, and could not recommend either one in any way. If you do go with either, I hope you update.

 

Did he perform for you like engine stuff or bolt on modifications?

 

nelson will do almost everything from basic tunes, cam swaps, bolt ons, full engine builds. He even built a full exhaust for me.