you guys are comparing apples an oranges.
my .02:

99SIs car would not have been totally rebuilt, had his motor not been burning oil already. it was consuming, and we figured it would be best to freshen it up and while we were doing taht , we knew it would see lots of RPM so we went ahead and balanced and blueprinted the motor, and installed ARP rod bolts (extra insurance).

Having said that, NA vs Turbo will always be a debate. NA costs less money or equal to a Turbo build , but it will make less power. it depends what you are looking for.

heres what i mean:
A custom turbo kit from us would run $3500 installed. It would give you roughyl 210-220whp at 9psi. (dynos to prove it) and around 180-190TQ.

For $3500, you cant make 160whp on an LS if you went NA. if you went LSVTEC, it would still only be 170-180whp AT THE MOST and that would be pushing the limits of your budget.

which car is faster? well what if i told you the Boosted LS doesnt hit peak power until 5500 RPMs. but the NA car makes a strong Powercurve at 4000rpms?

Its all about building a WELL BALANCED car. with that in mind, what is your budget? it differs if you have $1000 and $3500 to spend.

if you had ROUGHLY $5000 to spend. i would do a turbo kit with a small turbo T25 or str8 T3. I would get a GOOD suspension and sway bars and clutch and flywheel. it would make for a great peppy car, and you would have gotten the suspension and clutch to handle the power.

Reason why i say dont go NA, is that i would hate to see you spend all the money on a motor that is peppy and fun, and neglect suspension, clutch, flywheel. For $5000 you could do a NA car, and it would be fun, but LS rods are weak when it comes to sustained high revs (you mentions auto-x and mountain runs) and it would take an engine build to really get the power, something you prob dont want to do with 95k miles on your motor.

if you want to do an NA car, i would actually reccomend selling your whole LS swap for a good price and buying a good GSR swap or ITR swap. much more relaible and much easier for an NA build.