Working with electronics my whole life, the theory behind it is easy but in practice, it's so much more difficult. Yes you could run a haltech for the 6. I guess if you really wanted to, you could run one for an 8 as well but the options aren't there for that kind of application. I'd be interested in speaking with you about getting a motec on the cheap though as I heard they got out of selling cheap before their first product ever hit the market. They do know their stuff though and when it comes to getting everything setup, that is what matters most. Now if you are only looking to throw a turbo on there and bump the boost up to say 9-10psi, you need to make sure you are running really good gas and that you NEVER run into a lean condition. I'm defintly not one of those guys that says just go buy an SRT6 and be done with it because I can't leave anythign untouched myself so go about it and do your research. You need to get in touch with HDDP as he has done part of this and may be able to lead you in the right direction for some things.

Good luck