I know this thread is a few days old..but here'* my 2 cents worth. I just replaced a fuel sending unit on a 96 SE Dealer wanted $565 for just a sending unit...no pump motor.. GMPartsdirect.com has it for 1/2 aprox $284. Autozone said they could order one froma aftermarket company for $199.
So I got one from a junk yard for $20 and it had a fuel pump attached. I know junk parts can be risky so I tested the one I found with a Volt Ohm Meter. On a 1996 the sender works in a range of 0 to 90 ohms of reisitance. I hooked up the leads and moved the float up and down. the one I took seemed to be pretty accurate..installed it and it'* working great.
I know that it'* a lot of work...but you might want to pull it first and match it at the junk yard or see if a local GM dealer has one in stock...and go and get a good look at it so you know what your looking for I had to pull mine out of a huge stack of sending unts for all makes and models of vehicles, that they had pulled and stacked up.. They had just sent a ton of them to a rebuilder but they had what I needed.... I read some where here at BC that some of the later models have a sending unit that ranges drom 0 to 240 ohms. So figure out what you have/need. if you put a 90 ohm sender into a Bonnie that has a 240 ohm gauge or vice versa you'll have accuracy problems