real battery terminals make a differnce?

Do the lights dim even when your engine is at a good RPM (try putting it in neutral and revving to like 4k). If so, skip to the next paragraph. You can try running the amp wire straight to the alternator. But chances are that you're not going to solve your problem with that. If you don't spin your engine way fast (I'm talking like 7-8 grand) then get an overdrive pulley for the alternator so it spins faster. Many HO alternators actually give less power at idle.

To ground the alt, you ground the engine block. The alt is grounded to the engine, which should then go to the chassis. If you want, you can ground the chassis again from one of the alternator mounting bolts, but you don't need to.

If your lights are only dimming a very small amount (at idle), then you can try a cap.

and what does your "carputer" consist of? Computers can draw quite a bit of current, up to probably 25-30A @ 12V if it's a good computer. You may just need an alternator that is better still. By the way, if you're having problems supplying enough power to your car, then I wouldn't run a computer in there 'til I got those power problems fixed.

My computer is already istalled and everything so taking it out means leaving me without any tunes.  But it consistts of :

epia m1000 motherboard, soundblaster audigy 2 nx usb sound card,usb gps reciever, 20gig 2.5" laptop hard drive, latptop dvd/cd-rw, 7" vga touchscreen. 512 megs of ram, video is intergrated.  60w power supply and ITPS DC-DC regulator.  I think that is about it. 

My lights dim when my engine is at normal driving 2500-3000rpms the alt is supposed to put out 150amps at 1500rpms.  They do not dim too bad at all, but they do dim and can get pretty bad when im really cranking on the stereo.  I do not listen to the stereo at that volume all the time but i would like to be able to and not have my lights dim.  I was just going to add a batcap ( here good things about these) because of it ablitly to discharge high amps for long periods of time and to stablize my system voltage.  I will call alterstart tomorrow to see what they have to say.

Well, with his computer, it's not so bad. That's why I asked what it was. If he even had a 200W power supply, at 12V, 85% efficiency, that's about 20A. It really depends on the computer setup. But using the Epia stuff and a laptop drive, it is indeed much less.