BAD Headbolts but GOOD Valve Buckets?

Hey all,

My 07 CLK63 is at the mechanic's for running very poorly at low speeds. I also saw a cloud of white smoke a few times out the tailpipe on a WARM startup (after running for a while or a short drive)
I bought the car knowing it would need work and have barely driven it once or twice since then given the engine runs poorly - engine feel shaky at low RPM.
The car was sitting for about 2 years as the previous owner was dealing with health issues.
When on the highway, the car drives quite strong - I've only driven it once on the highway (the test drive before purchase)
At low speeds, the car feels very shaky and there's an active oil leak from the valve cover gaskets
I sent it to a shop that took the valve covers off and said they recommend changing the head bolts (as they look original) and the valve buckets are my choice because they don't have any wear on them.
My question is this, should I pay $1000 to have the headbolts replaced and leave the valve buckets?
It'll cost an extra $1800 for the buckets to be done through this shop (parts and labor included in both prices). Pricing in Canadian Dollars

Could I save a few bucks by sourcing the parts myself?
They quoted me $20 per head bolt and $47 for each of the 32 valve buckets
Labor to replace head bolts is $600 and valve buckets is $1500. Total cost would be $3000 CAD or $2400 USD (taxes in - with parts and labor)
The shop claims I don't need the valve buckets because they look solid and unworn.

I have asked them to send me pictures before I okay any work. I'll share those pictures soon.

Is there anything I should ask them to test or check specifically while the car is there before I OKAY the work they recommend?
Just want to make sure I am not going to spend and then find out the issue runs deeper than just headbolts / valve buckets...