Re: high maintenance?
Welcome to the forum, and congratulations. You probably bought one that just had the snot driven out of it and zero scheduled/unscheduled maintenance done on it, unless it just quit on them. Many others have had similar experiences. This is becoming more and more common as the manufacturers extend service intervals. I will say, on mine, once I went through everything, right after purchase, I haven't had any problems in 4 1/2 years, save a bad EGR Valve and a lazy Oxygen Sensor. (Maybe I should knock on wood?) I tend to be overly proactive and do all scheduled maintenance, some more often than required, plus I now know how things are supposed to work and sound, making it easier to tell if there is a possible issue. I also have a DashHawk installed so I can monitor most drivetrain functions in real time.
Edit: the mayo. in the catch can is normal in the winter time, or anytime there is a lot of moisture in the air.....especially if it's cool. It's not uncommon to fill the can in less than 800 miles in the winter time. Better to have it in the can than cycling it through the combustion tract and risk contaminating the O2 Sensors and Catalytic Converters.
The seal in the thermostat housing is a fairly common issue, especially if somone had it off and tried to reuse the same seal. I never had a problem until I went to a cooler thermostat and tried that. I haven't found a place to buy the seal without buying the thermostat (stealer), and I've tried using gaskets which tend to seep after a bit. Best thing I've found is to bite the bullet and get it from the stealer....ugh!! No coolant sensor on these. Once you've insured the integrity of the system, you shouldn't have any problems, and just check the reservoir level when you're emptying your catch can or checking the oil.
Fuel economy (on the Hemi) should be ~12-14 in town and ~16-19 on the highway. With my mods. I usually get 13-15 in town and a best of 24.4 on the highway (over 346 miles)....normal is 22-23 mpg.
05 LX/RT & 06 WK/GCO, modded similarly, MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tube headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 plug gaps. 20 in. SRT Reps.