I have used Lucas UCL in my 2007 Civic LX since it was brand new. The engine idles a tad smoother and the car seems to reach speed with less effort. I feel that using Lucas UCL while breaking in a new engine is a good practice because clearances are tight and the added lubricity should help to reduce heat (my theory - not based on fact).
I also add one bottle of Redline SI-1 to the tank of gas that I use just before each oil change. Since the car is not driven very much (6,300 miles total since it was new in May 2007), I change the oil once every 6 months. This is overkill, but the only thing hurting is my wallet.