street driven year around, I would drive it hard occasionally, but I dont want to have the feeling of something busting when I accelerate full throttle.

If you have the funds to build it now and plan on doing it later down the road build it . You will save on the labor of having to drop the motor twice.The thing you have to keep is the full cost of everthing like clutch gauges fuel system etc.

Here is a straight answer "don't go for maximum power on a stock engine"

I have all the supporting mods needed, all sitting in the closet Just need the tt kit itself and possibly internals. As for fuel I will be fine with the supplied kit, the basic fuel sytem if sufficient to 580 whp, near the max of the stage 2turbos.

Stage 2 is rated for 700hp. If ur goal is 580 then yes you should build it. Although it all depends on how u look at it. I'm at 540/500 and no problems whatsoever. Stock block with supporting mods. Does the extra 40hp justify you spending the extra money to build? If so then by all means.
If it were me I'd build the block and go with a stage 3 and shoot for some good numbers. Look at Mr. Squeeze build and u can do something similar. Built motor will hold up fine.

The basic fuel system that comes with GTM kit is at a safe max around 580whp. Sure it can go a bit further but why push it. The stage 2 turbos max around 620whp right?

My goals are actually around 525whp. My reasons for the short block build is not for higher numbers, but for ultimate engine longevity. I hope to keep the car for 10+ years.

I have read Mr. Squeeze build up, quite impressive. It sort of makes a build up for stage 2 hp levels not seem needed, but as I mentioned before, I want a sort of speak "bulletproof" engine to last the test of time with daily driven exposure.

i understand this logic, there's nothing worse than worrying if rods/pistons are going to go flying when you floor it. Especially if you intend to keep it long term. I'd like to go turbo as well, but why invest so much money if there's a possibility it may not have the longevity?

I say, if the money is no object, then definitely build the motor first. But if the money is the concern, then go SC. just my 2 cents.

SC just isnt fo me....Money is always a concern, but I prefer to do everything right the first time. The basic built short block fully assembled and installed is what, roughly 7k. Just need to put in more overtime;)

Longevity is where the "variables" come in. Ur installer, ur tuner, ur driving habits. Get a good installer/tuner and you will minimize detonation. 525whp is fine. Now if ur gonna baby ur car everyday and not see full boost motor will last a long time. If u follow all the speed limits you most likely wont have a problem.
Now if you're gonna use the stage 2 the way it was meant to be used sparingly you'll be ok.
If ur gonna slam the gas n drop the clutch at every light that turns green ur motor won't last built or stock. If ur gonna hit 150+ everytime ur merging on the highway ur motor won't last built or stock.
If ur gonna redline it from 1st thru 6th ur motor won't last built or stock.

If u use it right and maintain it properly it should last quite awhile. If a 'Vette tries to show u up spank em, big event coming up that happens every few months at the track u can run down the track a few times.

You know your driving habits and how you treat your car better than anyone else here.
Just research, figure out what u want and if its worth it take the plunge!

I've been boosted 5k+ miles at 12lbs and my G rapes almost everything out there from a roll. I have no complaints and I push it hard at 12lbs. Worth every penny.
That being said when my motor does give up(built or stock) I have a backup car and already have funds set aside for the motor to be built.

Good luck OP

elperuano, are you oem internals?

On a side note, whats the optimal compression ratio. Most aftermarket pistons are sold in 9:1, but I hear 10:1 is better suited for the vhr. However, 10:1 needs to be custom ordered. Any input here?

I am stock block :)

You mention reliable for up to 500+whp, but also remember once you crack open the engine you can have even more problems. Just because you have stronger internals does not mean they will last as long as OEM or work 100% fluidly with what you are doing. Many times have I seen a built motor dead 2 months later, and not because of a bad install but because of a quality part just breaking.

Will it be cheaper overall to do a built motor with a TT now, yes, you save on install cost. Will you need it in the next 3-5 years? Probably not with how you plan to drive. Also, a good investment is a boost controller which will allow you to run up boost to a nice 500whp for those fun runs and then dial it back for everyday driving.

Perhaps it might be a wiser to get the gtm stage 1 short block rather then me bringing parts to a shop elsewhere and having it assembled/balanced.

I have the new greddy profec ebc. I will be running internal wastegates. Not sure if I will experience boost creep or not with stage 2. I am aware of the creep issues on the stage 1 internally gated though. Will be 3" downpipes to 3" dual exhaust.

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This is a little bit misleading yes a built motor can fail , most of the time its because of not being assembled properly. A engine that is built by a good machinist and uses quality parts will not fail .

I have 10 k miles 600whp low boost on my build motor built by a local machinist that I trust.

Soon to be 700whp high boost .

I am not saying 9/10 die, I am just saying he wants reliability and a built motor does not always equal reliability when it comes to cars. Especially if all he wants is ~500whp for daily driving it seems like a waste and could cause more headaches. A good tune, install and boost controller would be an overall better investment where he can drive daily on a lower boost setting and then turn it up for fun runs. Plus in 5 years time he might be onto a new car, different path with the Z, or something else and the built motor was a waste.