The Euro should handle it unless you are pulling something huge in really hilly terrain. We just finished a cross country trip with on the order of 800lbs total inside Jeep and a UHaul 5X8 with a total weight of 2,000-2,500 lbs on a stock TC, with the GDE EcoTune and TCM tune, and had zero shudder.
The Euro runs about $450 and SunCoast $695 but on top of that you have to add shipping to you and shipping the core back which is probably another $50-100 depending on how shipped. I don't know about ATS but I do know there has been some recent chat about a heavy duty product from
http://www.torqueconverter1.com/ that may be in the $200-330 range. Alternatively if there is a good local torque convertor shop they can probably build what you need.
I chewed on this for quite sometime until installation of the GDE Stage II turbo forced my decision at which point I went with SunCoast for no better reason than they are 3 hours away and did the install (TC, Transgo kit, tranny clutch pk inspection) for a fair price with a 2 year warranty on the TC. I did find out later, from the parts manager that I've know for years, that the local DCJ dealer had installed several SunCoasts in Dodge truck so the could have done the job (yes I know about dealers but this one is a good one and, anyway, the tranny is a standard Dodge truck tranny and installation of a TC is not a special CRD "thing" as long as they use Loctite on the bolts).
SunCoast strongly recommends the Transgo kit (minus the resistor which I understand no longer comes with the kit) mainly because if replaces some weakish OEM parts. I'd concur that while you are in there this is a good upgrade.
Finally regardless of who does the install 1) locktite on the bolts is critical; 2) follow torque specs to avoid warping things and 3) ABSOLUTELY CRITICAL use only ATF+4. The latter is very important and sometimes has to be impressed on the shop's head with a club as some members have found out.