From my perspective what crab said about hardware/software is essentially true. I have spent big $$$ over the years buying a lot of application-dedicated hardware only to see most of it rendered valueless by a bit of cheap (or free) software. I would however agree with Redhat - invest in a hardwired compressor/limiter and read the instruction manual a couple of times. Eradicating RFI from your chain will be your biggest headache. Stock up on clamshell ferrites and bypass caps. All Electronics has them reasonably-priced with a flat $7 shipping fee and no minimum. As to software, there's plenty of it out there. I wouldn't pay money for a bunch of functionality though. I doubt you'll ever use it. I pound out all my stuff with Audacity. It works well, is open-sourced so improvements are available often, and has a very short learning curve. And its free!
http://www.sonicdownloads.net/download/Audio/Audacity/Years ago I pirated with a Valiant. I recall originally bypassing the 2nd audio preamp completely because most of the bandwidth filtering was there. Later on I had a more knowledgeable friend do the conversion work properly, but there was really very little difference in doing it the right way. It was a great rig, built like a tank, and blew out a very potent signal. I never needed a monitor to know where in the program I was at - you could easily hear the audio vibrating those 6146Ws. I also miss the WHOOOOMPH! it made when the carrier was switched on. These silly little MOSFETs I now use lack the romance, and the hardiness of that old tuber - have fun with it Longwire!