I have used the Lucas UCL and I was not really impressed with the product, I was at Wal-Mart yesterday and the stuff goes for about $9.00 a quart, I used it when it was $20.00 a gallon, now its like $30.00 a gallon, MMO is alot cheaper at $3.64 a quart.
My cars ran the same whether I had Lucas in there or not, with the Maintenance Dose of MMO I could really feel that the car was more responsive, in my El Camino that has a carburetor it feels like I have a new carb on there. I really think this MMO keeps everything lubed in the fuel system, and in doing so everthing is working perfectly. I also feel that MMO lubes the cylinder walls and I have noticed easier starts and my spark plugs look perfect, meaning no crud on them.
I also feel that the Lucas UCL is thick and though this may not be a problem in the warmer weather I would have some concerns about the thickness in the colder weather.
A member on this board turned me onto MMO and I am very happy with the product, I even use MMO in the fuel on my:
1) 2 Lawnmowers
2) Snowblower
3) 2-Cycle Blower
4) 2-Cycle Grass Trimmer
I am about to pickup some Redline SI and I plan on mixing that with the MMO since it is a cleaner and also lubes the top end.
Since using MMO I have no driveability issues with both of my cars, one being fuel injected and the other being carburated.