clerk im going to give you the comparisons for the 38's in a nutshell, and this is through experience:
the g model is slighty more agile then the j and l, especialy at low speeds, and yes it does handle like a spit, but it starts to compress around 301 mph, the j model starts to compress around 380mph, but with the dive flaps out the l model can get to about 450mph before it starts to compress. i have found that if you do compress you can trim your elevator trim all the way up and cut the throttle. DONT PULL ON THE STICK, especialy in the l model, between the trim and dive flap, if you pull back on the stick you WILL rip the wings off (trust me, learned that one the hard way with 3 kills under my belt
) the j is a decent aircraft, well balanced in speed and manuverabilty ( my favorite of the 3). even with flaps out i have trouble with the l model at low speeds. i love taking guys to the deck in a g model, going full flaps and scissoring them. the g model practicaly hovers if you do it right.
people tell you to turn off auto combat trim when you fly a 38, i only turn it off to help me recover from a dive, otherwise i keep it on.
rudder...... the 38's have HUGE rudders. with nose mounted guns and the huge rudder the 38 is great at snapshots. snapshots alone are hard to master but you can practice on the drones offline, just fly outside the circle and then fly back in perpendicular to thier flight path and lead the target ALOT. there is a post somewhere about snapshots with a video (common help me out fellas).
also try and hook up with murdr in the TA. he taught me to get a 38 to do 3 immelmans in a head-on merge back-to back- to back. quite a neat litte trick when you have a plane that cant climb as well as you. thats another thing, 38 have great climb rates (g model excluded) when you are fighting and aircraft like a p47, some spits ( dweeb16 excluded), try to keep em climbing, burn thier e, i find it easy to rope-a-dope guys in a 38, you dont even have to kill the engine to get rid of the torque that usualy screws up single engine planes because a 38's props turn in opposite directions of each other. just go up, hang on the flaps and pull the nose slightly over 90 degrees straight up or slightly short of it. 38's are nose heavy planes so will full flaps and throttle cut after the stall horn sounds she will nose right over and if you roped the guy right, BAM! now he is the target!
i love the 38! that and the pony are the only planes i fly anymore. i hope i helped and have fun!
p.s. imho the only downside of the p38 is that she is a big target. enemies will land hits on your p38 that would normaly miss smaller planes. thats why i try to come with a friend or else you might as well be shark bait.