Since you have verified these cylinders are ECI/Titan, with the associated trouble with them, if it were me I would replace all cylinders with new Superior of Lycoming. I was in your very same position 3 years ago and had I known about the trouble with ECI/Titan cylinders I would have done it immediately and saved lots of heart ache and expense. Unfortunately I did not have any idea bout Titan cylinders and by the time I addressed the issue I had to do a full TDI after the nickel coating went through the whole engine. Mid 2000's ECI Titan cylinders are little ticking time bombs ready to sluff off the improperly installed nickel coating. Just my opinion.
i have these 2000's ECI/Titan nickel coated cylinders running well for 200 hours... yet. but i am mentally prepared when the time bomb explodes.
is there any source that addresses the typical problems associated with these cylinders and what we can do to avoid them?