PCM requirements for LS1 swap
Keep in mind that 98 PCMs are the oddball... if possible you'll want to go with a 99+ LSX PCM
The 98s are a popular choice for hybrid's like this since several companies offer premade wiring harnesses, but if you can get a 99+ PCM and a 99+ wiring harness, your tuning options increase significantly.
there are several tuning options out there for 98s so it's not like you can't tune using a 98 PCM.... but the 98 tuning options currently are much more limited (since they were a one off year, hard to justify custom OS's for them)
HP Tuners supports 98s as well as EFI



