I've praised the AlterKtion and my experience with it in building a hemi Challenger convertible in the suspension section of the board before, but I'll state again, that as four forty-fied said, Bill Reilly is great to deal with and his stuff works. The ALterKtion has competition now that didn't exist when I bought, but I would still go the same way again.
I had no clearance and fit problems with the hemi and TTi headers, and shaker alignment was good too. There is very tight clearance from my Stage V valve covers to the pass side shock tower, and it has struck a few times, but very minor.
A few of the teething problems I had that were promptly remedied by Bill with personal service.
1. He was changing out sway bar designs from a splined bar with billet arms to a fully bent bar, and my AlterK got built in the midst, leaving me with no sway bar attachment. He provided all pieces, freight paid, to add the new sway bar brackets to my ALterK and lower arms, and because I had already powder coated, comp'd me the sway bar ($225) too. It was a hassle to be sure, but he handled it very professionally.
2. AFCO had an incorrect shock in one box from Bill's inventory that ended up in my kit. I ended up scratching my head for hours (days) trying to figure out what was going on. Tale of the tape - one shock was longer than the other. Bill promply sent the correct part before I returned the other wrong one.
3. In mounting my steering column I realized I didn't have a lower steering shaft bushing. This was very late in the build and I needed to get the piece pronto, he sent me a Delrin bushing he machines in his own shop 2 day air - no charge.
4. In the process of taking the u-joint off the column again to add the bushing, when I drove out the interference fit pin, the original U-joint cracked. Replacement comp'd.
5. After 100 miles on the road, I broke a spring on the coil overs. A look at the break confirmed hydrogen embrittlement, the springs were chromed, but apparently with the wrong process to eliminate this potential failure. He sent me QA1 powder coat springs gratis before I even pulled the springs, so I would have the parts to go right back together when I pulled the coil overs. He also offered to take back the AFCO shocks if I wanted, for new QA1 adjustable units. He didn't have to do this. But he did- and I accepted, again on the honor system that I'd return the AFCOs.
In every case where a problem was identified, Bill was responsive. If you deal with enough aftermarket companies, you realize what a different attitude Bill has.
And by the way, the Challenger REALLY handles.