What am I best to do then in terms of repairing my Turbo, (going to try that first and hope it sorts it

) should I send mine away to get reconditioned or just exchange mine for another unit or what?

Where/who should I be dealing with in either case, to get mine overhauled or to exchange it?
Also what are my limitations in terms of upgrading at this stage, bearing in mind that the engine is almost standard apart from a stage 1 chip, -31 actuator, and a Mongoose s/s exhaust and I don't want to put really alot more strain on any other O/E parts?!