Fitment, sound and performance questions about exhaust combo's

[Razor_nl]

At the moment I'm running a JDM GVR4 6bolt engine in my '96 GS. It came with a 4G63 non turbo (european, it's basicly a GST with the turbo ripped off) and I'm still running the stock exhaust. Obviously it's restrictive as hell and I can really feel it holds back at high rpm's, especially in 3rd 4th 5th gear. Also the dyno shows only about 250ehp and that should be more.
So now I'm looking to replace the exhaust with something bigger. I'm planning on a new downpipe (eliminating the cat) and a catback.

For the downpipe I'm looking at 2 options:
- Megan (cheap)
- Apexi GT (for the brand and material)

For the catback I'm looking to the following:
- HKS HiPower (good price, good brand, decent sound)
- Greddy EVO2 (best sound I've heard from an exhaust! downside is it goes under the suspension and price)
- Apexi N1 (good brand, decent price and sound, used a lot so has to be good)

Size of the catback doesn't matter a lot to me. Currently I have about 250ehp, I'm planning on 300-320, nothing extreme, it's my daily driver nothing else. So 2.5" should be fine but 3" wouldn't hurt either.
Money is always important but I'm willing to pay any of these.
I don't care if my exhaust makes some sound but I absolutely don't want to get deaf after a long highway drive.

I was looking mostly at the GT + Evo2 combination. But I'm a bit anxious if it won't be too loud (no cat and 3" catback)

So my question to you guys is... will all these combinations be a 100% bolt on or do I need to modify flanges or anything? Will the combination I said above be fine with sound or will it be quite loud? And will there be any parts that give noticable more/less power than another choice?

Hope you guys can help me out and clear up some things for me.

 

[boostngsx]

Iv got a GREDDY 3" setup on my car and it isnt to loud. Its louder inside the car than out. If you are driveing long distances on the highway I wouldnt recommend it. Keep in mind if the exhaust you buy is to loud for you , you can always get a silencer for it.

 

[Razor_nl]

Ye that's true, but I think a silencer looks way less sexy than a tip without one.

And I do care a lot more for the sound inside the car than outside.

Maybe I should go with a HKS or N1 then.