Just curious of the cost for the entire set-up with twin turbos...I do like it, but not certain what is involved with something like that.
It depends what route you want to go. I went the junk yard route because of the learning curve. I blew up a couple engines learning to tune but again they were $500 each. Here is what I do to the engine if I am going to boost it. I make sure the engine has more than a 100,000 miles on it so I don't need to open up the ring gap. My current engine had a 180,000 miles on it. I leave the heads completely alone but do replace with new stock lifters and LS9 head gaskets. I also run chinese head studs. If your car isn't lowered you can run the GM performance parts (hummer) pan. It's cheap. That is how I started. You can modify your stock wiring harness and run HP tuners and have it tuned. We ran 5.99's with that set up and chinese turbo's.
Since we started I have upgraded to the Holley EFI HP, put on a Holley pan, replaced the intake, and went to a better convertor, PTC. I have also added a boost leash and upgraded the suspension. That's about another $4,000 in cost but I plan to run in the 5.40's this year after all those changes and low 8's and still daily drive. Without all that we ran 5.99's for a total of around $3500. I used the same fuel pump, lines, fittings, etc. that I already had on my big block. I also used the same transmission by modifying the holes on the stock flywheel. To this day that flywheel has held up. I run the stock coil packs, water pump, etc.. from the donor engine. The turbo's are On3 performance 61s. I have zero issues with them and they are $340 shipped to my door. I purchased used wastage's and blow off valve. They have still lasted and are currently on my engine.
This is just off the top of my head but hope this helps. Now all the haters will get on here and talk about the extra $4,000 I just spent. What's funny is most big block people spend thousands trying new heads, intakes, carbs, etc... Yet we are supposed to forget how much they spend trying to make their cars faster. For $3500 I ran in the 5's. For an additional $4k I am hoping to run some 5.40's.