Well I have to agree and disagree with TC.
I love my 2014 Laramie Longhorn for all the reasons that he likes in the RAM truck line. Yes this is my first personally owned diesel, not my first to drive. Have driven Class 8 trucks down to 2500 diesels and I love this "modern" diesel. I have had minor glitches to some major issues, so far all covered by recall or extended warranty from a recall. Issues, SCR-DPF replaced by TSB due to code, DEF tank replaced after AEM, now having updated EGR replaced under recall. I have installed an external oil cooler due to 2014's failure rate of the stock cooler, which turned out to be shavings from the cylinder heads manufacturing process, poor QC. I also tuned post AEM due to the poor engine performance. I drive a lot, cover the state of Oklahoma teaching and tow a toy-hauler RV, new one weighs in at 8K. Old toy-hauler weighed in at 7K+ and made it to Montana last year. Empty post tune my 3.92 geared truck runs 26mpg highway summer, 24mpg highway winter, yet my average is 25 summer and 22 winter. I switched to Rotella T6 before FCA recommended due to my experience as an engine builder and knowledge of engine oil. Here in OK we only have at most a 45 cents per gallon difference between gas and diesel, at present we are paying between $1.40 to $1.70 per gallon for diesel and gas is going for between $1.19 to $1.29 per gallon for E10, non E10 is running $1.40 per gallon. I have monthly fuel usage and cost analysis for all my vehicles so I know my RAM runs 8 to 10 cents per mile for fuel and my wife's GC eco runs 7 to 9 cents per mile, my 1995 Z71 5.7l gas runs 13 to 15 cents per mile. So TC can do the math, however, I have heard fantastic things of the 2019 HEMI. Now towing I have not claimed any astronomical mileage that I did not calculate manually and verify with my monthly fuel usage reports. Our old RV netted from 11 to 13mpg from OK to Montana. The one trip with the new heavier RV not so much trip out 8 mpg on the trip back 11 mpg.
Now to agree. The FCA does produce two different 3.0L V6 diesels, the one in the ProMaster vans are the ones referred to by TC, and is by all accounts a stellar engine. The EGR issue was not addressed until the 2020 engine and TC does not believe in the new approach, I am inclined to agree but will wait and see. Why? Well the first overhead cam was built in 1909 but was scrapped due to failures, dominate today. I can not believe the disdain that FCA has heaped upon their customers. It should be illegal to treat the people who buy your product as bad as some of the RAM customers have been treated. The programming on this truck is one of the worst examples of committee development. I love my truck but have done things to improve what may have been blemishes. The exhaust system is a trademark of EPA regulations and is designed for Class 8 over the road engines, so as TC says, daily driver short runs will net serious exhaust issues. A lot of highway allows for the engine to stabilize at operating temp, as well as lets the exhaust system to function more like it was designed, thus avoiding issues. I also know that Cummins, Ford, and GM diesels have all suffered the same exhaust issues as the eco, including Fire Apparatus with SCR/DPF exhaust installed. The EGR is also a mandate from the EPA, which may have solved issues in 1990 but today creates more issues than it solves. With the more efficient SCR catalyst I, along with most of the light duty diesel world, believes that the EGR is crippling diesels.
So you must analyze why you want a diesel, your driving cycles, towing needs, and cost you are willing to pay. Why? Because in reality if you are wanting to haul a lot or heavy you may be better off with a 2500 diesel or a HEMI 1500. Fuel mileage savings are, like TC alludes, based upon cost differential between gas and diesel in your area, along with fuel mileage. Yes most gas engines go 100K without a spark plug change, the HEMI does two per cylinder, but my diesel doesn't use spark plugs. Changed plugs on my son-in-laws Tahoe at $9.57 ea. my cost. His oil change at 5K miles, my oil change 10K miles, yes I do OA every change and they are always good and looking better since the tune. Yes he nets about 12mpg running empty. Yes current small block gas engine routinely run 200K miles, my 95 has 400K on the clock of original drive train. It took my a few years to get there. I bought my 2014 with 20K miles on the clock now sitting with 126K, time will tell. I understand the clearance cost savings for a Classic, but you still need to analyze your driving cycle, DD equals exhaust issues, highway not so much. Also your towing weights, as the 3.55 geared truck cannot tow as much as the 3.92 geared truck and vs the HEMI rating.
Sorry for the long post. but in my world knowledge is power and to make a risk vs benefit analysis the more the better. Good Luck.
