LOL sorry but this was a strange thread from the get go when you said you need "need something with a lot more power / torque".
Is this your only car?
I can totally understand what you mean about having too much of a good thing.
About 6 years ago I test drove a Mini Cooper S John Cooper Works. Ended up buying a 1986 CRX Si off craigslist for about 1/8 the price. Had a CRX in the early 90's as one of my first cars and stupidly crashed it into a telephone pole :/ It was as fun (and raw) as I remembered. Will never sell, nor hopefully crash, this one!
Then about 3 years ago I wanted something a bit more exotic (with a targa top, ideally mid-engined) so test drove a new C6 vette. Same thing as the Mini: too much power and grip to ever reasonably use on the street, so I ended up buying a 1985 Ferrari 308 for about 1/2 the price. Any new V6 minivan will easily beat it 0-60, but NONE will get the hair on my neck standing up racing towards redline in a tunnel or kicking out the back end at 50mph through on ramps.
I certainly live by the motto "It's more fun to drive a slow car fast than a fast car slow"
Hope you enjoy the M5 more than ever. I certainly look forward to driving ours whenever I can prise the keys from my wife's hands

(drinks)