Is this possible?!

Is it possible to outrank my competitors when their pagerank is 4-7 in the first 10 spots of google, and my site is pr 0? They've got no onpage seo for this long tail (4 words) keyword and Traffic travis is saying that it will be relatively easy, although I kinda don't trust travis this time that's why I wanted to ask here.

Also I've forgotten the exact match domain is free

I wouldn't let the pr of a site intimidate you. Analyze the backlinks those sites have. If they got a bunch of highly related links with good keyword anchors, then you got yourself a hard fight.

Always possible, may be difficult though. PageRank doesn't always guarantee good rankings.

PR doesn't mean sh!t.

Only thing I look for is onsite (Title, Meta tags, H1 etc) and backlinks.

Just do an analysis of top 10 results for a ton of different keywords. You will see there are often a lot of PR0 and PR1s outranking the PR5s-PR7s etc. due to RELEVANCE.

Backlinks waaaay more important than PR.