Hi nickq,
For a bit more engine noise as opposed to exhaust noise, give the following a try.
1. New clean air filter - similar to genuine AR part - don't use a cloth / cleanable filter
2. New spark plugs as per the manufacturers specification - lash out and get the best you can afford - NGK Iridium or similar.. I was amazed how my V6 still managed to run ok with buggered spark plugs.
3. Have an Alfa Romeo EXPERT workshop clean the inlet tract / ports / valves with the magic solvent. Best left to someone who has done it before. Its a fair job on the V6. Given its direct injection, the V6 inlet track is not cleaned with fuel mixture.
4. Replace ALL the front upper and lower control arm bushes with polyurethane. Another big job but worth the effort. In addition to help direct engine bay noise and vibration to the chassis, the stiffer bushes will improve front end steering response a fair bit. Make sure the new poly bushes support caster and camber adjustment via upper control arm eccentrics.
5. Last resort. Remove the sound isolation from the passenger compartment side of the fire wall.
The car will be in a better state of tune, handle better and probably be a bit lighter - win, win ,win!