Safe alternative to fuel cell?

I'm getting ready to finish laying my 98 ranger frame. But gas tanks in rangers hang way the hell down so I was wondering if there was a safe alternative to a fuel cell or if I should just go ahead and buy one. I heard something about scrapeproof gas tanks but I didn't know how much to trust them or where to get them. Right now you can get fuel cells on ebay pretty cheap. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33556&item=7906854730&rd=1