Worth trying the sound generator mod that most of us have done. Just type in sound generator in the search. It's very simple to do and most owners settle on just removing the foam at the bulkhead end before entering the cabin, as removing both foam restrictors produces too much noise. Gives a terrific throaty induction sound when the throttle pedal is used enthusiastically but no real change to standard sound at lower throttle positions, ie cruising. This is not producing any difference to the exhaust sound but is still a very rewarding substitute, perhaps until you have found the exhaust system you want. Lots have carried out the back box delete where the exhaust back box is replaced by straight through pipes (check out these old posts) but many can't live for long with what they describe as an annoying loud drone at motorway cruising speeds. Horses for courses!