Im contemplating an exhaust upgrade but before I get stuck in replacing the exhaust what if any tweaks are there that can be done to improve the sound??? - ideally reversible mods in case I dont like it - I thought I read something about opening valves and suchlike but im very forgetful

anyone have any suggestions?

Im thinking maybe a quick mod to tide me over the remainder of the driving year and get the exhaust done fully while im not driving it over winter.

any advice appreciated!!!