OBD2 problems

[Curtis Mittong]

Whoever has knowledge of this stuff may want to contact me offlist.  I have
alot of dumb questions that are probably below your intelligence levels and
I don't want to clog up the list with too much "entry-level" chatter.

Background:  I have a 96 Impala SS.  I plan on making the LT1 into a 409
(4.030 x 4"...which actually makes 408.17) and totally starting from the
ground up.  I am tired of bolt-ons that make a certain HP, I want to tailor
each part to each other part and get a good reliable streetable engine.  I
am planning on output being in the 600+ hp range.  I can build bulletproof
engines that put out 1000 on nitrous with enough money and resources, but
what I lack is the electronics know-how.  I have the mechanical plans done.
Currently, in my little burg there is no emissions testing, but I don't plan
on living here forever, nor does my little burg plan on never testing, so my
baby needs to be street legal (or have the potential to be once a year).  I
have seen an LT1 with a stock PCM and an Accell piggyback make 592 hp, but
that was with the stock Optispark and it was pushed to the limit.  Its hard
to get the PCMs to reliably support more than 500.  I think with the right
tuning, I could get 650hp to pass a sniffer, but without OBD2 compatibility,
I'm not technically legal.

1) Someone with emissions knowledge; what do they check and is it all ok if
it passes the sniffer?  Or does it have to be a certain configuration?
Certain hardware intact?

2) Since Iive where they don't check, does that mean that I have free reign,
or is it still illegal but no-one checks?

3) Is there maybe an OBD2 computer that will easily support that much HP?  I
want overkill, not just squeezing out 642hp.  I may want to add nitrous or a
blower later.

4) Is "emissions legal" as easy as using "street legal" or CARB approved
parts?

What I really need is someone to take my hand and walk me through this.  My
main problem is this:  I can take my parts to the machine shop and get what
I want and I can build the engine to support the HP.  But, if I take it to
my "EFI guy" and he says that its not set up to best use the EFI he had in
mind, then I have already failed in tailoring all the parts together.  I
want to know enough that I can make accurate plans to make compatible
systems work best.  It can make the difference between a few extra HP and a
detonated engine.  Thanks

Curtis Mittong