2004 G35 6MT - need non OEM amp to replace OEM -suggestions please

Hello all, I just had to replace the head unit since it was draining my battery, CD motor was running even when car was off and radio was working at times. While replacing the radio with an Alpine iLX-W670 they mentioned that the amp might be also bad but seems it was a lose wire which they fixed. Next day the radio is working but no sound and it takes about 40 minutes for the sound to come out. The car audio place said that this might happen and if so will need to replace the amp. Ive already spent a lot of money on the new HU and the new radio, can someone suggest some amps that will work with this radio, with the connections of the old amp and that won't break the bank?

Hello all, I just had to replace the head unit since it was draining my battery, CD motor was running even when car was off and radio was working at times. While replacing the radio with an Alpine iLX-W670 they mentioned that the amp might be also bad but seems it was a lose wire which they fixed. Next day the radio is working but no sound and it takes about 40 minutes for the sound to come out. The car audio place said that this might happen and if so will need to replace the amp. Ive already spent a lot of money on the new HU and the new radio, can someone suggest some amps that will work with this radio, with the connections of the old amp and that won't break the bank?