Yes you can install the pipe without any major noticeable effects, though to maximize the benefit of the exhaust you may have to change the fuel injection mapping.
It will make the exhaust come out those holes instead of the the tail pipe. Just take your vehicle to a muffler shop and have them remove your muffler and put pipe in it's place. No restriction means...
In the US, the cheapest grade of gasoline is best. The owners manual calls for 87 octane and the 805cc engine has a low compression ratio, which has no use for higher octane fuels. I've done 34000...
You can drill a hole in anything as long as you have a strong enough drill bit and drill. But why would you want to drill holes in your exhaust? The exhaust piping is there to route exhaust gases...