I have a Sanwa ERG-WRX in my 4wd and it's over 4 years old. Imported it from Hong Kong and it cost £60, should have been £90. I have a Savox 1258 in my 2wd and it's not a patch on the Sanwa for accuracy.

Like everything in life you get what you pay for. Let's say you buy a £40 servo and it lasts just over a season and it dies you would be miffed. Spend a little more and you'll save in the long run.

I've looked at Futaba bls451, is it discontinued? Replaced by the 452?

I've also found a Sanwa sdx 901, used, £46? Seems reasonable, I'm just trying to find how old it is but it looks mega strong!

452 is different, it is a slower servo with higher torque, not the best choice for 1/10th steering. 451 isn't discontinued as far as I know but you do have to shop around to find them, there are a coupe of UK shops that do them at a good price.

If you want to compare servos, this is a great site...

http://www.servodatabase.com/servo/futaba/bls451

HTH :)