My suggestion to you is to do all you can to stay with a replacement LQ1, if you choose to do otherwise you'll have to deal with the electronic side of the issue.
For '91 the trans behind the LQ1 is the 4t60-e, now that may not seem to be much of a concern but the ECM in the car is programmed for the LQ1 & the 4t60-e.
You look to drop in another engine of choice & now you have to reprogamme the ECM to accommodate that replacement engine. The mem-cal inside the ECM housing is specific to the LQ1 for that year & that trans.