What can I expect from a magnaflow exhaust?

Honda Civic 2000 lx
B18c vtec DOHC swap (and all the corresponding parts like the manifold)
AEM cold air intake
But I have a stock exhaust pipe.
I recently purchased a magnaflow exhaust with 2.25" piping and I would like to know how much hp I could be looking at gaining, now I'm also well aware that in some instances there would be little to no gains at all. But I read that for upgrades on stock civics. Any help? Just curious

You have to turn your stereo way up

Cold air intakes don't work with fuel injection which is metered plus if the intake is short and is under the hood the air will not be cold whereas EVERY modern car has a cold air intake already with the intake outside the engine compartment

More exhaust noise. You may think it performs better but the dyno does not lie; maybe 1 hp increase if you are lucky.

  • What problems should you expect to have buying a car with 300k miles? Looking to buy a 7 year old Honda with 300k miles cause it's really cheap. What are some problems I should expect to have?
  • How much should I expect to buy in fees when buying a new motorcycle at a dealership? I want to buy a Kawasaki Ninja 300 ABS that has an MSRP of $5,299 in the state of California. The dealership I plan on going to is Fremont Honda Kawasaki. I would be financing the motorcycle. Up-front, how much should I expect to pay, assuming I buy the bike at MSRP? Thanks! Also, what information would they need? ID etc? I'm 17 and have no permit or license for any sort of vehicle. Could my mother buy it for me? She has a Class C license only.
  • Can I use a different nut for my motorcycle exhaust? I have Vance and Hines pipes on my honda shadow and a nut came loose and fell off somewhere. Can I put any type of nut on there as long as the threads are the same or does it have to be the exact kind that came off because the kind that came of was a cap nut that prevents over torque.
  • Bike totalled how much should i expect back? I had a driver run a stop sign and cut me off, they never stopped so my insruance covered my wreck, i'm thinking its totalled and wondering how much i will get back, its a 2012 Honda Fury abs, just bought it in November brand new from the dealership, it only had 2500 miles on it. Any help would be much appreciated.