What About DEF Trucks?? Should I buy one??

I would also stay away from the early DPF models.

 

New trucks are expensive, and the SCR system is only a part of that very high cost. If you're sure trucking is going to be your livelihood the next 6 plus years and you feel you're at a place who pays right and has ample freight, buy new or almost new (epa 2010). You may have some issues in the beginning buy hopefully once these are addressed and properly maintained going forward, the benefit should be realized and you'll be glad you bit the bullet.