I tend to agree on the "you could buy an M3 for that money now" argument. I have blown about $8k on my Stage 3 mods including labor which isn't too bad. I have definitely looked at how much more it would have costed me to get an E92 M3(new). I am still about $12,000 off actually. Then again it depends on how much you paid new as well but BMW doesn't discount that much.
The LSD is a great idea but for $3k I am up to $11k in mods from Dinan not counting wheels/tires and downpipes. After all is said and done maybe I should have bought an M3? I guess the M3 doesn't have our torque but they handle great right out of the showroom.
335i coupe Montego Blue Dinan stage 3 tune, Advan RS wheels 350whp/365wtq
1994 Brooklands Green Acura NSX Comptech Supercharged 390whp/300wtq