Hi BobStoc:
MSRP is $265. Dealer prices range from $250 - $300 in So. California. Haven't seen the upgrade personally, but those who have it seem satisfied. Guess it's a personal decision, based on how much you drive, where, your last upgrade, if any etc.
Your 2001 gs430 is most likely a gen 2, so your v7.1 upgrade Lexus part # is PT219-GEN023-07. You can verify your upgrade version and part # on Lexus.Com. A Toyota dealer may give you a slightly better deal for Toyota part #PT219-GEN23-071, which is also supposed to work.
I hear they're also selling on ebay & craig's list for about $100, (http://newyork.craigslist.org/mnh/pts/581607998.html) but I'm a bit leery about paying some unknown person for something without knowing if it realy works.
There's downloads on the 'net, but getting it to work seems a bit tricky. (See http://www.mininova.org/com/1088929)
ANYONE: I'm looking for someone to hook me up with ge 3 & gen 5 upgrades, here in So. Cal. Please PM me if you have any info or leads for me. Thx! B)