I'm sure you choices would work fine. Many of the manufacturers have say that all their 100 in/oz. + servos are 'ideal' for 1/8th buggies. You've picked some lower cost servos with very reasonable numbers. I ran a Mayhem with a Futaba 9451 steering and JR590 for throttle without any problems.
However, many of the other posters have suggested digital servos which are supposed to have a big advantage over the analog one's and that is holding power. I interpret it similar to the following: torque will let you turn the wheels while your car is landing off a big jump and your car has lots of g-force driving the front wheels into the ground, holding power will keep the wheels in position when you hit the big rut in the track during this turn.
If you're going to race competitively, you might want to consider the jump to some digital servos now instead of upgrading later. I would also recommend 175 in/oz + of torque for steering if this is the case. If you're mostly bashing or casually club racing, your choices will probably be fine. You have the right idea looking for specs rather than brand. Most people ruin a servo or two because of their own errors and write off the brand telling everyone it's junk.
BTW, I'm putting together all the pieces for a RC8 when it's released and I'll be running a ACE 1015 (200 @ .108) for steering and a Futaba 9451 (120 @ .10) for throttle. It's about a $90 and $80 combo.