I bought some breaktech grooved disks not so long back which came with free pads. At low speeds they clunk and at speed they sound like a jet engine firing up. These cost 220. Should i try changing the pads agian or the lot. Iv got jdm sti with gold brembos.

 

it sounds like the pads are slightly moving in the caliper,

it can happen when using diff pads other then oem.

think u can get anti rattle shims but dont quote me on that,am sure someone can clarify it,

as for the braktech discs, i had them with mintex pads when i had them on my old 4pots and they were brilliant at stopping,

remember the free kevlar pads u get are only just slightly better then the oem pads

 

Grooved discs can make a buzzing noise.
Lots of after market pads move slightly in the calipers making the clunking noise. Anti rattle shims won't make any difference as the noise is the pads moving up on the locating pins when moving (or down when reversing).

 

I'll try different pads and hope it improve things, cheers!

 

Or have a look at the info on these quiter than your conventional than your grooved discs as The finer slot pattern is what makes these sport rotors more silent in operation whilst still offering pad degassing and removing dirt dust water and debris from the braking area.
http://www.ebcbrakes.com/automotive/...rs/index.shtml