V-tech and Springs

Well i got a quastion for all the 5th gen prelude owners.
I got a 97 prelude nothing much done to but an intake and exaust for performance. but my quastion is when i had my exhaust welded on after a couple of days my v-tech started to act up when i get upt to 4700rpm the car goes loud and the rpm go so slow i never had that before and i have no idea what it could be.
My other quastion is my suspension i tried coilover and those sucked the ride was to bouncy. Then i went with H&Rs 2.0 in front 1.75 in rear those ride so smooth bu the car makes noices when i hit anything on the street, so im wondering should i raise it up a little and go with the Neuspeed 1.75 and 1.5. Would those be better and less noise and will the ride stay pretty smooth?

THANKS

umm.... about the V-tec i think it might be the Cat. I had a friend that need a new one because in the high rpms it was not moving. Also about the springs not much about supsension but it might not be the springs it might the sturts or shocks. not the springs itself. Because if you have stock sturts the springs have so much pressure on the stock struts that is not uses to it and will ware faster.

I think H&R and neuspeed are similar in quality. They are pretty much the same. I've heard some people say that they didn't see much difference when they lowered with H&R, but that's the only bad thing. I've heard so many positive comments about them. Personally, I'm a neuspeed fan though.

km is right though, you need some good struts if you lower your car.

Well i have the problem in the rear suspension and i have tokoco 5 way sdjustible.

What kind of noise is it making?