I guess everything depends on your budget and how much you're willing to spend.

If you wanted to go with YS, I can recommend a 160DZ over the 140 or perhaps try finding something like a 175CDI or 185CDI. If you look through the "buy & sell" section you might find something reasonably cheap and in good condition.

I know the O.S 1.60 has been used by plenty of people in the past with good results. For memory, they have great performance especially when paired it with a good header and tuned pipe.

However, if the model was previously set up for glow it wouldn't be too difficult to modify it for EP. That opens you up to lots of different budget-friendly motor/ESC options through to what the pros are using.

Servos depend on budget once again. I would perhaps recommend buying the best you can afford and when you upgrade your model you can always reuse the servos.