Which autobox behind an LSx for a Street/HPDE car?

Say you wanted to make the compromise of keeping with an auto for a daily driven and track day vehicle (think congested traffic commute, so all sorts of compromises), what would you pick if you were looking on a reasonable GRM budget ($2-500?). Vehicle is an e46, so bonus points for playing nice there. 4L60/80 w/ microsquirt control sounds like the easy button purely on the face of it if you're likely to be using megasquirt for the efi end of things, but I really don't know. I'd rather go that route over HP tuners (better fit for me for at least the near term), but could be convinced.

TH400 with a manual valve body might do it for me, but I have no confidence in my ability to work with modern electronically controlled transmissions.

Looks like the 5l40e is on the list, at least partially. Since that's the trans already in the car, that sounds promising. I may be able to come at that from the BMW control end of things since one generation of the e46 ecu's seems thoroughly hacked.

So is a refreshed 5l40e up to track day use behind a warmed up 5.3?

In reply to bluej :

there are a couple or companies that make paddle shifters for the 4/6 speed electronic gm boxes. 4l60/80 6L60/80

https://www.tciauto.com/paddle-shifter-without-display.html#

The BMW non-AWD version, the M82:

" It is designed for service in vehicles up to 4000 lb (1814 kg) GVWR and in service was mated to a selection of final drive ratios 3.42:1, 3.73:1, or 3.91:1 depending on the carline. The 5L40-E had been designed for 1.8–3.6 L engines with a maximum of 250 ft·lbf (340 N·m) of torque. It was underrated when used in combination of M57D30 engines. As the M57D30 rated torque output of 390/410Nm."

It appears on the surface that that transmission won't last long behind the power of your 5.3 but I only know what I read on the internet so take that with a shaker of salt

In reply to MrChaos :

That's interesting. I'm ok w/ bumping the stock location, though. 

I need to research 5l40 vs 5l50 differences I think. 

it seems like everyone goes with 4l60,4l80,6l60, or 6l80's for a reason

5L50 isn't really up to the torque requirements, is it?  I remember idly looking at the specs on these and they seem interesting, and Megashift can control one, but I don't know about  5.3's torque not hurting one fast.

200-4R if you don't like the 4L6x's ratios?  4L80's seem to have a pretty nice ratio spread like the 200-4R did.

MrChaos said:

In reply to bluej :

there are a couple or companies that make paddle shifters for the 4/6 speed electronic gm boxes. 4l60/80 6L60/80

https://www.tciauto.com/paddle-shifter-without-display.html#

639$ for that?!?!? Insanity. I could adapt a paddle shift from a sim rig for a LOT less.