It just depends on what you want for the car. If you intend on porting the E-7's to try and really get any power out of them, I'd say no. I had a set of ported E-7's on my '93 LX until recently, and it ran very well. If you just want a fairly strong 13 second street driver, and you KNOW the E-7's are in good shape, then yeah, go ahead and get them. Of course, it's gonna depend on the rest of your combo.
A few weeks ago I put in a new motor with Twisted Wedge aluminum heads and a bigger cam and jumped up about 75 hp over what I was at with the stock heads. It will cost you as much or more to work over a set of stock heads as opposed to buying a set of Trick Flows or Edelbrocks or something along those lines.