should i change the exhaust piping?

i have a 1994 accord ex 2.2 VTEC engine i have an injen short ram intake and a arospeed rear universal muffler. i also just bought an arospeed exhaust header. i have not installed the header yet but do you know of any sprays i could use to loosen the bolts on the header and heat shield that work fast? the rear muffler has an inlet diameter of 2 1/4 inches but my accord exhaust piping is 2 inches only should i change the piping to 2 1/4 inches or just leave it as it is now or if i change it will i get gains in horsepower with the modifications i have. i also have new resonator to replace the factory one but i don't know if i change the piping should i leave out the resonator or does it become really loud if i take it out. i have heard some people say you get horsepower gains by taking it out but some say it doesn't matter?

PB Blaster is the best stuff to use to loosen stuck/rusted on bolts, give that stuff a minute to penetrate and you should be able to get any bolt off. as far as going to 2-1/4 pipe, it wouldnt hurt anything, plus you'd prolly make more power, however if you dont add a resonator than thwe exhuast will get very loud.

go buy a cat back exhast system if you have the $, best of luck on the nuts and bolts, i had the same trouble the other day

PB Blaster is the best stuff to use to loosen stuck/rusted on bolts, give that stuff a minute to penetrate and you should be able to get any bolt off. as far as going to 2-1/4 pipe, it wouldnt hurt anything, plus you'd prolly make more power, however if you dont add a resonator than thwe exhuast will get very loud.

Take that advice to the bank.

If u have a hard time taking off rusted bolts cuz it is stripping and stuff.... go buy a vise grip pliers. 99.9% of the time u will get it

For the spray PB blaster like everyone is saying is the best.

For the piping... i thought stock piping is like 1.5" or something. But yea 2.25" is the best piping size for any N/A inline 4 engine except for those fully built motors. A resonator will rob u from power but if u are gonna do basic bolt ons then u wont even feel the difference. Just put that resonator in place of ur cat and then u will feel the power.