Magnepan 1.7i and want to upgrade to something bigger....louder....what do I get?

Really depends on what sound characteristics you’re looking for in addition to more punch.  Also, what’s your budget and are you looking for new or used?

@brachtober if you want punch, it is to do with your room more than the speakers. you need to take time with subwoofer integration, crossover with mains dialing in and DSP bass management with corner bracing in mind.

What is your budget?

Depending on your budget and new or used, check out PS Audio

Aspen FR30 for larger rooms or FR20 for medium sized rooms. 

Legacy Audio ROCK! Look at the FOCUS SE. 

You sound like a Cerwin Vega guy.

Rockport excels at most everything! 

Tekton.

The. Living. Voice. https://www.livingvoice.co.uk/

I had a pair of Magnepan 1.7i's  and transitioned to Tekton Double Impacts.  Absolutely no regrets.  Much more dynamic, better/more accurate imaging, far greater power handling.

Try a pair of Vera-Fi  subs (30 day money back)  https://verafiaudiollc.com/products/vanguard-caldera-12-active-subwoofer

hth