System for a 2.5i wagon

[SPT]

Need some advice out of everyones experience on here. When I bought my wagon it already had an aftermarket system on it, but it drones quite badly when on the highway, and I can't really swap anything out on it because it's all welded together.

I do enjoy having a nice note on the car, but am after something that will be a bit kinder on the ears when on the highway. Maybe even go back to stock if someone has a spare system available and then go from there?

I am pretty open to ideas, but at the same time don't want to spend a fortune. Will be happy to pay for something that's worth it at the end of the day though. Also, quad tips would be desirable so I might look into that.

But yeah, open to everyones ideas and interpretations!!
Thanks!

[Surge]

Depending on how bad it really is, perhaps a tune could improve the sound and reduce drone. I think matt from kidotuning can make some adjustments in that area.

Just another option I guess.