Booyaballer : TTIs instructions are very well thought out, so Id have confidence an OEM starter would fit. That being said Id encourage you to go with a mini starter "while you're in there". Note you really need to jack car up a lot to get long tubes in from underneath.
Speaking of TTI's instructions they clearly warn of Keisler/SST fitment cautions and am wondering how you will get around the clearance issues I raised in my earlier posts? I called TTI when it happened and they said " we warned you!". They offered a angled extension to help a bit with the cross pipe clearance but that still left collector and tube clearance issues. I have my suspension set at 24 1/2 height middle of the wheel well and used all three spacers SST supplied to lift the tranny tail shaft up to the max in the enlarged tunnel. That gave me 2 1/2 inches of ground clearance at the collector flange with the TTI340BE-C2. That's not enough for standard 4 inch speed bump, and its in exactly where the car comes down over a speed bump.
The pic below is with my TTI shorties. I have 4 inches exactly at the lowest point which is the rearward clamp. Visually, a LT header will add another 1 3/4" below this pipe. The collector will Narrow it down a bit, but the flange will be wider yet again, getting back down to about 2 1/2 inches of clearance.
Not trying to be argumentative, but both wanting to learn and save you an expensive mistake. Very curious. And if your interested I have 2000 PowerTour miles on the the TTI340BE-C2s that I'm not using. (I raised torsion bars up to 25 1/2 inches to do tour with around 3 1/2 inches of clearance). Very good condition with some scraping on passenger side lower tubes and slight pie cuts taken at collectors to angle upward.