Attention grabbing/ get pulled over all the time : HKS Hi Power (Sounds awesome, kinda raspy on a ka)

Stealthy/ deep & growly : RSR exmag (very loud)

Stealthy/ quiet : Blitz Realize TT

Cheap/ mellow : Megan racing type 2

It really boils down to n1/canister style vs conventional muffler type exhausts. I'd go on youtube and type in s13 exhaust there are a TON of videos on there. The tone will change greatly depending on your motor. All of the exhausts I mentioned are $450+ too... with the exception of the megan racing one.

I've owned a bunch of different exhausts and the only one I can say that I truly didn't like was my apexi n1 dual. It was quiet but I got pulled over left and right because it was big and shiny. Cops tend to target large shiny n1 canister style exhausts. I used to get pulled over driving at 2k rshared_pm in 5th gear with my HKS Hi Power, but not even a backward glance with my rsr at 5k rshared_pm with my wastegate blaring. It's kinda funny actually.