Fuel Pump On Its Way Out?

[Shadex]

Hey all, just recently i put some coilovers in about a week ago, and ever since then my fuel pump has stopped being noisey lol.

When ever i used to go to accessories you could hear the sound of it priming, and now you here it for not even a second..

Secondly, ive noticed a like high pitch whistle coming from the engine bay ( or what sounds like ) when i hit high revs 5000+

And it also feels like i have lost alot of power anywere from 4500rpm upwards, feels like its just not pumping any more fuel in to it..

It was obviously a aftermarket pump cause it was so noisey, i got it with the car so i don't no what brand it was.. Its a R33 S1

Does anyone no if this would be the problem or could be something else?

Thanks in advance.