RE: LA .10 any good?
I've got somel LA series engines and have never worn any out. They all run with castor. I use the .40s for 80 mph combat and the .15s for RC combat and just fun. The .15 is a pretty hot engine for $60, it runs all day with a 8x3 at 17,000.
The .10 is 2/3rds the size and weight of the .15 and about 2/3rds the power. Their power is proportional to the .15. I've heard mixed reviews about overall satisfaction with .10 sized engines but never have heard any complaints about .15s.......
...the question is, if you could add 33% more power for only $5 and have it only cost you 2 ounces, would you do it?