Just do the idle reset and relearn as if the battery had been disconnected for a while - start the car without touching the gas and let it idle for about a minute, then turn on all the accessories like AC, put the car in drive and crank the steering wheel back and forth. This lets the car learn how to maintain idle both with no load and under max idle loads. Then after you've warmed it up a bit go for a spirited drive about 10 minutes. If you didn't do this when you first put in the new D4U1, and have a high idle or a car that likes to stall, just disconnect the battery for 5+ minutes and re-run the procedure.
An LPM (Lifetime Performance Module) is just a chip for the computer (like a superchip except it doesn't suck). It can be tweaked for a bit more horsepower with a stock engine, but I wouldn't bother unless you have mods that need a chip like a different MAF, exhaust, supercharger, or such. The 'lifetime' is that it can be reprogrammed.
