unit_399 had posted his results with the 858 chassis radios receive mods on this forum. He stated that the 2999 is a downgrade from the original device in this chassis. He did point out that the diodes were an improvement - however.
The main reason for not using a 2999 in most other radios, is that this part of the receive circuit really doesn't need the extra gain. This extra gain - in my own experience as well - has only made the receiver circuit overload the following gains stages; the net result is unwanted distortion. After re-aligning the receive circuit to compensate for this extra gain with a SINAD meter, the only thing you have gotten out of this mod is that the 2999 has a slightly lower noise floor. But AT THE ADDITIONAL COST of having a shop re-align your radio's receiver. If you do that mod w/o re-alignment; then you will have distortion. What gain is that?!? In the end, there is little/nothing gained with the 2999 mod.
G0HZU also contributed a lot to this forum concerning this swap and the misuse of this transistor in circuit. I have found that this mod should NOT be used at all in some radios altogether. Most Galaxy, Ranger, Uniden, and Magnum radios for a start. Some older Cobras may benefit; but not unless the receive re-alignment is done.
Soooo; it is up to you . . .