Dynamically an M135i/M140i won't feel much different to your 428i. A bit more agile thanks to its shorter wheelbase and slightly lower weight, but the rear axle is in a better location in the 3/4 series vs. the 1 series, and it makes the car drive better IMO.
The M135i/M140i will, however, be MUCH faster than the 428i. On paper it doesn't look so different, but in person you can really feel that extra power/torque, and the sound is much better too.
If you want a BMW to really excite and make your dingle tingle you'll need something from the M Power stable, but unless you're prepared to buy something much older you'll have to massively increase your budget.