It was 70hp on a heavily modified truck with larger injectors. That's not going to happen on a stock injector truck. It would drain the injectors and probably lose power.
I've stacked the old Diablosport with our PCM/TCM tune years ago and there is absolutely no difference in power or 1/4 mile time. It puked and ran a tenth slower.
When it's all stock, you can notice a power increase...if you can keep the trans from slipping and jerking. Combine with a trans only tune, it's probably worth 70rwhp. Both PCM/TCM and FICM together is a disaster. Through the years we've worked around the FICM by making changes to the PCM, which basically returns the same results.
The later FICM reflashes limits some of these changes, so updating the code to an earlier flash or an adjusted FICM file will yield the same results as the earlier flashes.