Dear "desparate and frustrated" ,
I'm surprised you haven't been to
www.mymonte.com
There are many resources for modifying the 3400 SFI, from basic bolt-ons to indepth build ups. Take a look at the 3400 SFI in my signature just to get an idea.
Everything from headers, port/polish, throttlebodies, heads, performance exhaust, boost, nitrous.....just pick your poison.
Some other forum resources for 3400 performance are those such as Aleromod.com, MyMonte.com, Malibuclub.ca, GrandAmGT.com, 60degreeV6.com, FullThrottleV6.com, N-body.net, gmV6tuning.com, just to name a few.
Some places you can check for starters:
(please note, I do not endorse, nor approve of any of the following vendors)
http://www.rsmracing.com
http://www.milzymotorsports.com
http://www.turbochargedpower.com
just to name a few. Sorry if I missed anyone, not by intent.