You won't be totally happy with ANY engine you install (even a K series) because you will want/need more power. There is a happy medium that you have to set for yourself which includes things such as: budget, time, and driveability. If you have a lower budget and won't be able to build much - save up for a GSR swap. If you can afford to buy extra parts and have the time to install them correctly - stick with an LS. ...if you're going to continue to utilize your stock engine, then put your money torwards suspension.

-jonathan