One note on this, In recent years, pcmforless’ reputation has declined quite a bit. I don’t believe Alvin tunes the LT1s anymore (he had a stellar reputation and I actually used him personally) and there have been horror stories about Bryan’s (Brian’s?) tuning. It’s a bad habit to blame a tuner but when these people have then performed no fixes aside from removal of the pcmforless tune and the car runs good again, it kind of points to the problem.
Also, if you want a mail order, you better know exactly what mods are on the car. Those tunes can only be as good as the information you give them. If you don’t know the exact mods, datalogs can help them but there is still only so much they can do accurately.
If I’m allowed to, LTxtech.com has a wealth of knowledge and probably the most active LTx community nowadays. MoeHorsePower on that forum is a sponsor of ours and also has a great reputation he gave me some tuning suggestions on my never finished build haha.