Thanks for the info, I think I might indeed go for the MJE15030/15031 as drivers and the MJW3281A/1302A as outputs. Just one concern, won't the big difference in transition frequency and gain be a problem ?
Im a hobbyist, not an E.E. or pro tech, so take anything I suggest and carefully double-check with people who actually know.
That said, yes, you should look for a device that has a simialr or higher hfe gain. The various hfs gain codes (like MJE15030 "E" vs "G") is what you should look at. The gain codes will tell you "when I get these new parts, how much gain will they have".
The ft is a bit different. If I understand ft correctly, it is the frequency at which this device stops working (i.e. Amplifying). Because this is an audio frequency application, you require a ft of at least 20k Hz. Your original part was 60 MHz and the new part is way higher. That means both will amplify your audio frequencies just fine. The _trouble_ would be if your circuit is delivering higher frequencies, i.e. RF, and these newer, higher ft devices would happily amplify them. That's not good as you could get oscillation (motor boating) and the amp will work harder with no audio benefit.
Circuit designs, especially newer ones, have tiny capacitors in an amongst the driver or adjacent stages to act as a low pass filter and cut out any frequencies above 20k Hz (or so). The trouble if you use a newer device with higher ft would be if your circuit IS picking up RF and DOES NOT low-pass filter it.
Now someone with much more experience and knowledge can point out where I'm wrong and give you a better answer. I think your above choices are good ones.