new m3 owner with a few Q's

I recently purchased a 2009 E92 M3, DCT, fully loaded. I previously owned a 2007 335i, which I had tuned with a JB3. It was a great car, but thought it was about time to finally get what I've always wanted... so I did.



First off, the M3 really is far superior, even with the mods I had on my 335i, it's a different driving experience entirely.



Secondly, I'm interested in investing in some engine upgrades/tunes that would give me somewhat significant gains at lower RPMs, with gains at least 30 bhp. I've been through the forum several times, and have heard people rave about different brands/companies/shops/etc, but was wondering what the consensus is on a "must have" tune, and if it's worth the bucks.



Thanks in advance.