I would get the DSP5 and EFI, just remember although EFI is the best its only as good as the person that designed your tunes. Do lots of research and talk to the guys on hear that actually sell the tuning before you jump in. And welcome!
I also have a lly and dustin from diesel addiction has tuned my truck and I love it runs 12.35 on built trans and lift pump and his tuning. He does awesome work on lly trucks.
X2 on Diesel Addiction for tuning. He's in Wilminton N.C. probably about 4 1/2 hr. drive for you. He can install a DSP5 switch tune the truck and have you back on the road in a couple hours. Or you could grab a hotel and give him a day and get your trans built.