first off the MTX 7500 **** at the lows. ive had one if about 5 differnt boxes ranging from 1.5 cu ft sealed to 3 cu ft sealed, and 1.8 cu ft ported at 38, to 2.8 cu ft ported at 36. the only way it would hit low was 3 cu ft sealed, and the out put was OK. 2 cu ft a 40 was what sound the best all around for that driver.
the G5 is an amazing driver. great sound quality and very good out put. im willing to bet a g5 ported or with a rad will be louder and be cleaner then ANY kicker sealed. the L7 blow goats sealed, easpcialy that small of a box. i would think it would need something over 2 cu ft to be able to have any good or acceptable SQ.