under powered sub

Back ground: My friend and I are building a system for his 2000 Maxima. He has already bought Polk MMC6500 for the front, MMC650 for the rear, a Soundstream TRA960.4 amp, a pioneer head unit, and the soundstream SK4/8CAP 2 amp wiring kit.

Now he doesn't have enough money for the Sub and the amp for it at this time. So I was going to let him borrow my Crossfire BMF W12D sub (I've read 300 and 350 rms so I'm not sure)  and an amp that was giving to me, boss rev-265 85w x 2 @ 4 ohms.

I've spent about 2 hours today researching this subject and I have read so many things that I don't know what to believe. So far i'm leaning towards it's ok to run this setup as long as you don't turn the gain all the way up.

I also have an old Alpine 3528 amp 80w x 2 @ 4 ohms. Could I put these two amps together?

Thanks

I think DYohn might have over looked this, but the answer to this one is no, one amp or the other.

One amp or the other and if you try and bridge either amp, the sub must be ran in a series circuit or you will crispy critter either of those small amps.

The boss amp is 2 ohm stable. Would it still crisp it? If so should I run the 10-20 year old Alpine, it looks a lot better built and cleaner. Maybe it's underrated?

I think all signs point to the Alpine.

As far as your question "could I put these two amps together?"..I would say with authority, please don't.

As far as underpowering the sub have no fear...that is a myth. Like others stated watch the gains..Without getting technical and starting a posting war..lol, I can say an ignorant attempt to squeeze out more power then the amp is capable of for the sake of more volume can damage stuff.

I have seen cases where doing this actually damages the amp..not the sub..that's not debatable because I have done it myself trying to destroy a sub...I inadvertanly killed the amp after hours of trying to kill the sub.