Depends on what you want to be able to do. Look on the diablo web site and see what each is capable of doing and get the one that fits your needs. I bought the Trinity for the data logging time and so I could load multiple custom tunes on the tuner. What model and year is your car.
I have a 2014 R/T 5.7 I looked at the web site and to me being new to this game the tuners looked like they both did pretty much the same thing, they both could load custom tunes, it seemed to me the devices was the difference.
The trinity will log for up to 5 hours I believe. The intune for 30 min. The trinity also dose a lot of things that the intune will not. I don't use some of the features my trinity has but may use them in the future. Ther is a lot of difference in what they are capable of. If you just want the basics get the intune The trinity supports a lot of cars from Chrysler/Dodge plus Ford and GM. The intune DCX is only going to support 2011 and newer Chrysler/Dodge vehicles. The trinity will be able to be used for any car/truck that you may buy as long as it is on diablos list of supported vehicles. That includes diesel applications. .Trinity Automotive Handheld TunerinTune-DCX Automotive Handheld Tuner