No doubt about it, you will. Mainly because the Polk LSis are VERY hard speakers to drive. The difference is you will be seeing 300 since they are 4 ohm, and it will be an honest 300. I thought I had seen a test of an Onkyo receiver specifcally specing at 130 W and then only putting 60 into 4 ohms...

I use a 7700 with all LSi speakers as well...
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Speakers
Mains: Ninja Master Polk LSi9s
Center: Ninja Master Polk LSiC
Surround Sides: Slightly Modded Polk LSiFXs
Surround Rears: X-over+ Modded Polk LSi7s
Subs: Outlaw LFM-1 EX and Polk 505
Electronics
Sherwood R-972 (Waiting for the Outlaw (9XX)
Outlaw 7700 Amp
Oppo BDP-103
Signal Cable, Advanced Technology, and Outlaw Audio Cables
2 APC H-15s and an UberBUSS for good measure