Megasquirt 3

I'm going to be building a Megasquirt 3 for my conversion and I was wondering if any of you guys are running this setup?

Megasquirt is pretty neat stuff, but the factory GM computers are so well-known and modifiable that there isn't really much point. You might save a little money but you'll spend a lot more time. Just my .02!

It's cheaper and easier (in the long run) to keep the stock GM stuff and buy HPTuners than it is to rewire and setup Megasquirt 3 for an LS motor. If the GM stuff wasn't so bulletproof, powerful, and easily accessible, I would definitely recommend a Megasquirt. I'm still trying to spark the stock 4 banger crowd into running Megasquirts, and that would be an upgrade for them.

I'm mainly going this route because I do my own tuning and this is an ecu that I'm familiar with. I don't think it will save me any money initially, but long term it will likely be cheaper. Purely a decision based on my personal preference. I'm sure there's others running this?

Understood, but no, i don't think i've seen anyone do this swap and use a megasquirt. Hopefully someone will chime in for you...

I remember someone had a megasquirt, think it was an LT1.

As long as you get one of the MS3 units that has the expanded functions I like the idea (if you want AC or even launch control...). The past two years at school we ran MS on our FSAE car. Most of the issues we had were getting it to run a small motorcycle engine, we had a ton of sync/timing issues until we ground off a bunch of crank and cam sensor teeth.
For the LS series I'm sure the support community is huge. If I were doing a build from the ground up and needed an ECU I would consider MS3 as well. The box with expansion board is kinda bulky to put in the stock location if that matters to you.

I installed megasquirt 2 with Extra code on mine but that because I swapped in a SBC and then modified a LT1 intake to fit it so went 36/1 crank wheel and Ford Edis ignition instead of modifying intake for a distributor. For some reason people thought LT1's were really special up here and used engine prices were stupid. it was a fair amount of work but worked well.
You sound like you know what your doing so you won't have any problems.