I keep good records on my maintenance, but I never wanted to add it all up, well today I got the urge...and it made me realize what a great car I have and it's actually pretty economical on the wallet (despite what ANY of my friends or family say). I have done everything on the list below myself, except tire mounting and alignments.
I purchased my 300E in 2007 with 120K. It now has 210K. I have driven the **** out of it, but have also given it plenty of love. It has never left me stranded anywhere.
The number below would be easily double if I had to pay a mechanic hourly! Ouch!!!!!
I have the PeachParts forum to thank for helping me get through a lot of the jobs below and saving me thousands of dollars.
Purchase Price -
$1,500.00
2007-2012 Maintenance and Upgrades -
$16,270 or $3,254 per year, or $271.00 a month...still way less than a car payment. 
And what a car I get to drive in return....
Headgasket R&R, New Valve Seals, Machining - $750
Oil Changes - Every 6K - $60 per with filter - $900
Transmission / tq cvtr drains with filter x4 - $200
Rear diff drain x1 - $35
Euro Headlights - $250
Headlight Lenses x3 - $200
Euro Tailights x2 - $250
Front Corner Lights x5 - $200
FC Bearing Bracket x2 - $250
Fan clutch and bearing bracket pulley - $100
Reman'd Smog Pump - $100
Wires, Cap, Rotor - $200
Plugs x2 - $25
Radiator, Water Pump, Hoses, Temp Senders - $500
Bilstein FR/REAR Struts/Shocks and Mounts - $450
Rear Brakes x2 - $225
Front Brakes x2 - $300
Eibach Springs - Free
Sportline Front Bar with New Bushings - $100
Rear Parking Brake - $75
Front Tie Rods and Dampener - $200
1 Accident - $1750
Motor Mounts - $100
Rear Subframe bushings - $200
Rear multi-links - $350
Belt Tensioner x5 - $750
Belt Adjusting Rods x5 - $75
Belts x5 - $250
Voltage Regulator x2 - $60
120AMP Alternator - $50
New O2 Sensor, Used EHA, Used ECU - $150
Used OVP x2 - $50
K1 Spring Kit Repair - $75
Exhaust pipe patched - $100
4 channel amp wired to stock speakers, new headunit and small sub in trunk - $500
Used sunvisors, front door panels, armrest box - $200
Used door wood and center console wood - $100
Steering wheel and airbag from a 92 300CE - $100
Misc purchases (bulbs, filters,vacuum line,bolts&nuts, etc) - $700
2 windshields - $400
6 Sets of tires - $3000
2 sets of wheels - $1000
8 alignments - $1000