Grados aren’t particularly wide sounding. Getting the larger bowl pads helps but it doesn’t transform them; they’d still sound narrow compared to other headphones known for having a wide soundstage.

I have the 325is and those have plenty of bass for me. I have a love/hate relationship with them however. I love how full they sound still with low volume straight out of my phone with the Apple dongle. Perfect for nighttime listening sessions. I hate how shouty they can be at times. It definitely feels like you’re in the front row of a concert but that fatigues my ears rather quick.

It’s true what everyone says about Grados. They are great for rock. I also like them with Jazz but with a tube amp. These definitely don’t need amp and in my experience, they don’t exactly improve with one. Just ever so slightly tighter bass but nothing dramatic. And they become slightly less harsh with a warm tube amp. They just don’t “improve” like other headphones do when paired with a proper amp.

I really wish I could suggest the Sennheiser 560s but I haven’t received mine yet. They supposedly have some of the best out of the box tuning with great bass response but I wouldn’t know just yet. And since they’re open back and the drivers are angled like the HD 598, they’ll have a wide soundstage.