is 2.5 years of "gpa comeback" enough?

Quick question, how much GPA repair is "enough" to get one back on level playing ground with the perfect 3.8 cGPA, 22 y/o kiddos? Is there any amount? Could 2-2.5 years of full-time, upper division science courses at a 4.0 be enough to make up for a pretty crap undergrad showing? I understand that there are so many other factors and variables to consider and I don't want to turn this into a WAMC thread so I'm just thinking, from a adcom perspective, is 2.5 years + a bunch of life... is 2.5 years of "gpa comeback" enough?
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums