It's a new unit yes?
If so, I have found that they can take a week or two to 'fur up' a bit, and then they settle down. If it's really noisy, and you think there may be a problem, but want to see if it settles, call the retailer you bought it from now. If you make him aware of the problem, the ball is in his court. If it then has to go back, you will be in a better position, and he can't give you the 'You've had it a month now, why did'nt you come back sooner' bit. I must say that Renas are not renowned for being noisy. That dubious honour goes to Juwels' standard internals!
The spray bar bits can be had from your LFS, either that or contact the importer and give them the 'It's just that bit too short, and I'm really disappointed' speech. It usually works wonders......
sub.