Battle of the Heads
 

I cant decide between these two heads

1.Trace Elliot GP12 SMX

or

2. Ampeg Svt 3 Pro

either will go through hartke hydrive cabs

Im doing thrash metal but i want a David Ellifson/ Steve Harris sound
which is the better choice

And here I am, all ready to discuss the merits of Kohler over American Standard... :)

My upstairs head is a Kohler, but downstairs is an American Standard. I find they each have their applications.

Oh, um... bass amplifiers. Right.
Me, I'd go with the Ampeg. I'm biased: I've had an SVT3-Pro for almost 20 years and I've never had a single problem with it. Not once. Not ever.
Besides, if you're playing hard rock, how can you go wrong with Ampeg?

Which is better for metal? The Kohler or the American Standard?

haha you made me laugh so hard :D haven't seen these questions for a while...

Back to the original question. Only thing I can say to you is use your ears. ;)

You are doing thrashmetal BUT want to sound like ellifson??? Help me out here, because he IS doing thrashmetal :-) And if you want to sound lime him, drive his hartke hidrive cabs with what he uses: hartke lh1000 heads. Mids all the way, bright strings and there you go! Steve harris plays flatwound strings on totally different basses and plays marshall 12" cabs driven by hiwatt clones iirc.
Steve played trace elliot heads back in the time with a quite personal eq setting. Somewhere on the web theres a foto of this!

Between both heads you mention: trace elliot for what you try to do

Watch ellifson an harris rig rundowns on youtube!!