I liked my Cobra but sold it so I could save up for an Asp, but is the asp a decent cargo ship as well as a good explorer ship? I had it before but had to wipe my save, and can't remember what internals it has. I have a T6 transporter at the moment with 2 32 cargo racks, and 2 8 racks, could the T6 be a good explorer ship? Maybe change those cargo racks into fuel bins?
Asp is a perfectly good trading ship if you want to equip it that way - better than a T6. And as I understand interdictions are tougher since 1.4, not only does an Asp give you more cargo capacity, but much better agility, acceleration, and if you prefer to fly armed, the capability of taking out many would-be interdictors without much of a problem (I don't have any current experience, as I'm out in the deep black since before 1.4 dropped, and only now making my way back to the bubble...in my trusty Asp, but pre 1.4, I did many cargo and mining runs in my Asp, and would only run from a Python or above interdictor - anything else I would personally shred for inconveniencing me). A T6 can really do nothing but run from an interdictor and hope they aren't packing something that can punch through the shields before the FSD can spool up. Really, the next step up from an Asp for trading would be a Clipper/T7/Python.
The T6 is actually not a bad explorer, but unless you're rolling in credits, and can afford an Anaconda fit for exploration, the Asp is currently the best explorer out there.
Basically, stick with the Asp.