I'd say you've done some serious modding to you awesome machines!2Wheelfun
The 650i is what made the Brute Force a great pick when it was bought out, as the BF750i in '05/'06 were lacking allot in the handling department. I read somewhere that the latter half of '06 the BF750 handling was fixed but I'm not sure if that is true.
On the '007BF750i the 750i is set-up the same as the 650i and after owning the '05BF750i for 2 yrs there is a big improvement with the '007.
I still felt the shocks are too firm for a IRS 4wheeler even on the '07's & since I still had my '05BF750i, I switched out the WORKS Shocks, skid plate pkg, ITP Wheels/tires and a few other items over to the '007.
With the improved handling of the '007BF750i, lighter frt end feel which makes turning the handlebars easier & more so on the tight trails, this WORKS Suspended '07 BF750i is a dream to ride as hard & fast as you are willing to push it. The WORKS Shocks are fully adjustable and not only improve the shocking/damping/rebound but also smooth out the ride but these Aftermarket Shocks aren't cheap to purchase.
With a better set of meat for Tires & the wider stance the aftermarket wheels provide that tippy feeling is gone.
For now I'll hold off on a replacement EFI Model but I do plan on upgrading the EFI mainly b/c of the elevations of my riding range from anywhere between 3500ft to 14,000ft elevation. Presently my BF750 is rejetted one step b/c I ride at the 8000Ft-10,000ft range here in NM, then our trips to the Colorado Rockies every Summer get us up to 13000+ft in elevation.
I've tried many different tires lately btw the 2 Brutes and so far the Bighorn Radials are proven to me to be the Tire I need.