I have a 91 crx hf that needs a exhaust badly. Can I bolt up a si exhaust to a hf with no problems? Will I need to switch to a si exhaust manifold? I do plan on going to a N1 or a 2.5" but not sure if that will hurt me on the hf engine that i will be using for sometime till mine other motor thats getting built is done, wont be done till late this year. Any help or advise to do?