I tow close to 5k regularly. I use the 7pin, however I do not have a trailer brake control module. To be fair the passport does a pretty good job at stopping this weight on flat surfaces here in Florida. Hitch and wiring was $400 and change and I installed it myself. I don't remember how much the trans cooler was. But I'm glad I didn't spend the $2000+ as it was all pretty simple install. Not sure why the trailer brake control module would interfere with any electronics, as they are installed on many vehicles no problem.