If you don't need the extra power, don't want the hassle of the possibility of going to the service center multiple times for changing the engine oil, the 1.8 is good enough. If you drive like an aunty, the 1.5TC is more frugal than the 1.8. If your right foot is heavy, the 1.5 drinks more than the 1.8. Check my sig for the fuel consumption of the TC-P.
My engine oil is changed every 10,000km - will be going to the SC next week for my 10,000KM servicing and my first engine oil change too. If you get stuck in heavy traffic jams, the engine oil change will be between 5,500KM-7,000KM ymmv. I don't have significant traffic jams in my daily drive, hence the 10,000KM OCI in my maintenance minder.
Don't listen to the detractors of the TC engine. It's definitely more powerful than the 1.8 engine and rumours of overheat engine everywhere are just that: rumours. Yes, there is a confirmed case each in Thailand and Malaysia (that we know), but out of thousands sold now, we can safely say that they are lemon units - any manufacturer will have lemon units here and there not just the Honda Civic. My colleagues' brand new BMW 520i had an engine check prompt right after he drove out of the showroom, does it mean that the car is inherently problematic?
Do join us in the Honda Civic X thread to discuss more with owners if you're worried. We list down all the known issues and how to fix those - at least we are all being truthful and owners are sharing their experience with each other.
Try driving slowly over speed bumps , starting on hills , oh and parking ramps in multi story car parks are especially good at inducing engine knock. If this is true you need to push Honda for Ecu update