Maybe I should ask what types of suspension upgrades can be done to help for getting the power to the ground and keeping control for autocross style racing?
I already have over sized sway bars and extended length control arms with the tops being adjustable. (I believe the ones holding the rear end are called control arms?)
I have Bill Harper upper and lower A-Arms and have done both of the brake proportioning bold mods.
I already expected to have to do some major up grades to the cooling system and probably just get my 9C1 steering box rebuilt. Plan to add external coolers for steering and transmission and getting the biggest radiator I can fit. Have heard different theories on Electric or Mechanical fans as well. (Mechanicall push more CFM but Electric are less load on the system and can run with the engine off. When paired with electric water pump and electric fans it can keep a "race" car cooler between runs. )
A GOOD set of electric fans will flow plenty. It's hard for even a good set of electric fans to match the flow of a good mechanical fan (especially when measuring flow against resistance and not just free flow) but there are too many benefits to electric fans IMO to not use them. Better control, less power loss up top, as you mentioned the ability to cool while the engine is off and better cooling at idle versus most non-clutch mechanical fans.
Suspension and brakes, we are talking for 700+HP here? honestly, there is no limit to what "should" be done considering the weight of these cars when pushing that much power. No stock B body brake system, I don't care what tweaks are made, is going to be effective on a 700hp 4200 pound boat on an autocross track. I wouldn't use anything less than top end Wilwoods, the biggest you can fit behind 18" wheels, and expect to even go through those pretty often when really pushing the car around a road race track.
For suspension, every bolt in suspension part you can upgrade: tubular upper and lower front A arms, perhaps a coil over setup for adjustability at the track. DMR triangulation bars at the rear. RMS frame brace between the rear frame rails. All of this and you still have a wet noodle of a chassis. I would seriously consider boxing the chassis.
If I were to do mine over, I would have without a doubt built a watts link setup for the rear. I've installed them on several on other cars (F bodies) replacing panhard setups and the feel and control is just amazing. The closest you can get to late model independent rear cars. Tad (protools) incorporated a panhard bar into his triangulated 4 link and had excellent results on the road course/autox track. I still think a WATTS link would be the ultimate though as it should in theory eliminate any bind as the suspension goes through it's range of motion while fully controlling side to side movement.
The real issue you are going to run into with big forced induction HP on a road race car is intake air temps. Depending on what you use (turbo, blower, PD blower) keeping intake air temps in check is going to be paramount. At a certain point the intercooler is going to heat soak, IATS will rise and you'll either detonate and destroy the motor or if you're lucky, you'll have a computer that will read IAT's and pull timing accordingly and lose power.
1/4 mile racing is easy with forced induction, but road racing is a whole other animal. You see guys making 900+hp on eBay intercoolers making lightening fast 1/4 mile passes with no issues. If you want to see what works with road racing though, just look at late model track ready cars like CTS-V's, ZL1 cameras, Z06 Vettes, Hellcats etc... Some of them use 3 intercoolers and often times owners swap those out for even larger intercoolers for track duty. OF course PD blowers don't tend to be the most temperature friendly, it may be easier with something like a procharger.