is 175 for the catback sp for your year accord? if its not, itll have to be custom welded.
also if its 175 just for the sp muffler, i think its a rip off.
if youre looking for a quieter muffler than most aftermarket ones, sp is the one for you. but if youre looking for the loud sound, then you might be disappointed.
how loud it is also depends on the size of your piping and on your resonator, if you have one or not. the bigger the diameter of the piping, the louder. the resonator you pick also gives your custom catback a unique sound.
if what your buying needs to be welded on, i suggest letting a shop do it for you. as for the price, it varies by shop so call around your local muffler shops and ask for price quotes.
good luck!