Hi there guys

Can any1 help me,my brother and I we both have gc8 his is a my99 an my ones a
97...last year I got a walbro gss341 pump for my97 gc8 on ebay from some place in america when it arrived the box was plain brown box and at that time I didnt think anything of it til recently, my brother order a walbro gss342 pump from cjmotor in brisbane...the box had walbro written all over it in blue , anyway when he put the pump in his rexy there was a pretty loud humming buzz and compairing it with my 341 my pump was so quiet... Does that mean I got a fake walbro and will damage my ej cause im using a larger tomei arm 8265 turbo replacement from the td04 turbo? Is it normal for gss341 to be quiet? I just hope it hasnt been running lean in fuel an killing my engine.....