When I played the Spider II amp, no matter what guitar I played, the amp sounded the same. From el cheapo to high end guitars, it didn't matter, the Spider II has its own sound. It's not like plugging into a tube amp where the characteristics of the guitar come through, and changing guitars changes tones. That's what I love the most about tube amps.
The Spider II also lacks dynamics.
You probably also realise what you should do, just take that next step, maybe you should hang on to the spider till you have a sound your happy with.
IMVH opinion the Metal master is the most simple straight foreward, cant really do any harm, metal tone. I still have the death metal pedal, it has the most extreme bottom end boost there is in a pedal, i never turn it up though since its a really cr@ppy pedal, didnt toss it because nobody seems to want one! The death metal pedal only sounds 'good' when boosted with another pedal, on its own it sounds like p@@p.
Very high gain pedal is the MI audio Crunchbox, screamingly loud even if you have the first version, distortion is good but not very natural sounding.
If you like oldskool natural sounding drive i would suggest a Proco Rat or Boss OD-1 or OD-3. The OD-1(discontinued) is the most versatile of them all and is very low noise, just the best IMO.
Getting a good metal (like) tone out of decent gear is never much of a problem, try to get some analogue gear together, digital effects or amps always do lack dynamics, they do that for a reason, sloppy playing even sounds good under heaps of digital processing. Still if you actually want to hear what you are playing youll need to make that step eventually.
Best of luck and succes, great things will happen when your gear makes you work for it HARD
