Hell hath no fury .. etc.
I cant help feeling you've been royally screwed by your mechs. How they thought the timing chain was causing the uneven running I've no idea. As a previous post suggested a new set of mechanics would be in order.
My 31 year old Merc is my daily runner. It has cost me a fortune in detailing products! Upholstery cleaner, vinyl cleaner, car shampoo, chrome polish, the list seems endless. Oh, I did have to spring for a new air filter and servicing for oil changes.
Do I detect that if it wasn't for the lumpy running you'd be happy with the car?
I still get a rush when I come out of the house in the morning and se the majestic lines beckoning me. Perhaps it's a gender thing, men wanting a car as a mistress and women wanting it as a slave. A bit like relationships really!