ive tried a 112 valveking and i love the way it sounds, really clear and generally good but it seems to lack something that pushes it over the edge for me. I was wandering if a distortion pedal or better speaker would give it a heavier sound. I like songs by asian kung fu generation and it seems to lack a little crunch to my ears, im using a gibson bfg with a burstbucker3 in the bridge. Could it be the pickup???? I tried a cheapo guitar with a SD invader in the bridge and it sounded like total junk (even my mom said so xD, and she normally says "sounds the same to me") p.s. I know that the tone this band uses aint that heavy but id prefer somthin a little touch heavier than them
I think the speaker is by far the weakest point on the VK. It's built to a price point, so the transformers, caps etc aren't top notch, but a speaker+tube change can turn it into a decent amp.
^ +1

Also there are some simpler things like the dummy jack mod and using an EQ to open that amp up.
Between the velvet lies, there's a truth as hard as steel.
The vision never dies, life's a neverending wheel.
You need to visit the VK thread and the VK wiki.
IMO, an OD really helps to tighten it up and give you that crunchier and heavier sound. That'd be a good place to start. Replacing the muddy stock speaker will help too.