Magnepan 1.7i - Is a Luxman 505UX good enough

The best would be to audition the 1.7i at home or a dealer with your amp, if such options are available.
Otherwise there are a bunch of threads on different forums for the 1.7i where you can ask your question.
Having said that, the specs for your amp say it's 100w @8ohms & 150w @4ohms, I'd think the majority of users would tell you that you'd need upwards of 2 or 300 Watts with the ability to nearly double up @4ohm, though I've seen people who said they're happy with lower power.
I'd feel you may want more power in the long run even if you were initially happy with what you have now, then again you may find what you have is enough.

There was a review on Hifi+ for Peachtree 220SE with 220@8ohm &350@4ohm driving Maggie 3.7i, where the reviewer was quite happy with the output but it sounded like the speakers could use even more power.

it seems like the more power capability you put through these the more they show their magic, but the final judge of that would be the listener....

Thanks for your response sir... I do not have the option to hear the speakers in my home as the dealer is in another part of India...I did hear the Maggies in direct comparison with my speakers at a dealer in the Uk and hence the bug's bitten...

What you are saying is what I have read across most forums but wanted to know if anyone had tried using the Luxman with the Maggies and wanted affirmation that it will work.....

My opinion is that the 1.7i will sound very good, but not optimal. I think you need lots of current. I would look for a dual-mono amp.
That usually means more $$. But I have heard that 1.7's sound best with the powerful amps.

I really liked the 1.7i after hearing them directly against a Harbeth SHL5+ ... So I know they sound great but just worried if my amp can bring the best out of them.... Also my room is just 15 x 17 feet and I don't listen very loud.. Hence wondering if I can somehow manage with my current amp for the time being... 

I have had a pair of Maggie 1.7s for 2-1/3 years. I power them with a 30+ year-old Perreaux PMF1150 B in a room bigger than yours. Mine's about 16x20 with a 15' vaulted ceiling in an open architecture that opens onto the doorless main floor.

The Perreaux is rated at 100w into 8 ohms, and given its weight and size of power supply, I suspect it puts out 200w into 4 ohms. It is a great match. I can play them louder than I ever need. 

I throw a wide range of music at these speakers. I'm not a metal head, but I *do* have a special love for large scale orchestral music (Scherazade, The Planets, Pictures at an Exhibition, Elgar's Enigma Variations, etc.) and big band (Basie, Buddy Rich, Stan Kenton, Harry James, etc.) and classic rock (Beatles, Stones, Cars, Police, Pink Floyd, Bob Seger ...) and they never disappoint. The .7 and .7i series aren't as restrictive on power and dynamic range as the previous versions. You do want an amp that's *very* comfortable driving 4 ohms. 

I also augment the bottom with a pair of small subs that don't go real low (about 36Hz), but are easily fast enough to integrate with the Maggies.