Here is some good info I found about the swap on another site.
I have received some Standart Ram to Ram SRT parts swap questions. I am no expert but this is my experience. When I started researching and collecting parts, Ram SRTs were $40,000 plus. I loved their look, but not their price. Then I got the crazy idea to make mine look like one. I started out by getting the Service Manual on CD from links on the Dodge website... a very good investment. My SRT suspension parts came from salvage yards. You have to be careful with used parts (I like to see pictures of the donor vehicle) or you may get damaged parts...either from the accident (like stretched holes where the ball joints or tie rod ends attach) or unprofessional removal... even from a major salvage company (aluminum steering knuckles don't stay pretty after someone has beat them loose from the ball joints with a hammer). My rear axle came from a theft recovery where the engine, trans, and interior were stolen. I got the entire rear suspension for $2000 + 225 shipping FedEx Freight from Yuma, AZ to NC. That sounds expensive but I got a locking diff. with 4.56 gear in a Dana 60 with the aluminum cover and heavy duty brakes, factory flip lowered springs, Bilstein shocks, and stabilizer bar for my '05 regular cab truck. Check the cost of adding all that to the original axle! Before I removed the original axle, I used a permanent marker and made a reference mark on the driveshaft measuring across the slip joint boot from my front u-joint so I could later make sure I had the same travel in both directions so the driveshaft slip joint would not bottom out. It would probably be a good idea to have some way to cap off the brake line when you disconnect it from the hose going to the rear axle or the fluid will keep draining out slowly while you change everything. The springs, shocks, and axle all bolted in place. The speed sensor wiring plugged up correctly to the Dana. Since the speedometer gets information from rear axle revolutions, the gear ratio change does not cause the speedo to need recalibration. The brake hose and park brake cables all fit correctly. So far, I have not added stabilizer bar brackets or the power hop damper brackets to my frame. My driveshaft was about an inch too long, but I think it was more because of the 4 1/4 inch drop than the diff. being longer (I was expecting a 2 3/4 inch drop like the reg. cab SRT but have since discovered that the SRT frame has longer front spring mounts). I used a combo U-joint (Dana Spicer 5-648X from DTS Custom so I have not modified my driveshaft) and moved my axle 1 inch back by drilling new holes in the spring perches on the axle housing (I have seen spring flips that people have done where the axle was moved back they say to center the wheels in the wheels openings but maybe also for driveshaft fit?). For a QC, you will need the QC SRT Dana with the spring perches on top of the axle (QC SRT springs look the same to me). The QC swap should be simpler and may not require moving the axle back or shortening of the driveshaft. Ram SRTs come with 22 inch aluminum wheels but use a 20 inch steel spare, so aluminum 20's should fit OK. My 17 inch aluminum wheel will bolt on the rear but it looks like near zero clearance at the caliper. And now to the front suspension. First, I invested in the proper ball joint stud remover MLR-8677 tool from SPX. It isn't cheap but it was worth it to me. I probably have $1400 in my Reg. Cab front including the SRT springs, Bilstein shocks, and shipping. I have seen a picture of SRT steering knuckles where the letters 'QC' looked to be molded in near the upper ball joint location so I would guess quad cab SRT pieces are different. You have to change the entire aluminum steering knuckle (spindle) assembly. The SRT brake discs are larger diameter and use a much larger caliper. The SRT caliper has a wider bolt pattern were it attaches to the knuckle so it will not bolt to standard Ram knuckles. I got the entire '05 assembly with brake lines and the speed sensors (ABS) attached ('04 SRTs also have the large brakes but use a different caliper design). I left the hoses attached to the calipers and just changed it from the frame out. The brackets that attach to the frame are the same as standard Ram. I could not seem to get the speed sensor plugs unhooked easily near the frame so I left them plugged together and used the original sensors on the SRT hubs (hubs are the same anyway). If you look up the control arms on one of the trademotion.com sites, it shows a more expensive lower control arm for SRTs but I could not figure out why. I took many pictures underneath an SRT of the control arms and took the same angle pictures of the standard Ram control arms and could not find a single difference (even every weld pattern looks the same). The upper and lower ball joints and the tie rod ends seem to fit the tapers just right. The SRT knuckles don't lower the truck (it's all in the springs) but they did give me slightly different camber making the wheels sit correctly after installing the shorter springs. I have read that the Ram SRT has a quicker ratio steering. Where the tie rod ends bolt to the SRT steering arms is actually farther away from the pivot axis of the ball joints so it gave me slightly slower steering which I like. I have the 305/40ZR22 Pirelli tires on the 22 inch SRT wheels and the steering feels just right. If the SRT really has quicker steering, it must use a different gear in the rack & pinion. When I first read that the SRT had quick steering, I wondered why you would want quick steering in a 150 MPH truck!!!??? I would want to steer very gently at that speed. I was also told by a dealership parts guy that the SRT uses a different brake master cylinder. Everything looks the same on the outside but that doesn't mean the inside is the same. I may be totally wrong about this but, I thought maybe because the SRT front brakes use return springs, there may be something different about the valves that hold slight pressure in the brake lines. Or maybe the SRT brake master cylinder has larger pistons because the calipers use larger pistons... I don't know. I have the '05 SRT 4.56 Dana 60 rear end installed also with larger brakes and everything seems to work great. I love that 4.56...(I believe the '04 SRT came with 4.10). I can actually use 6th gear now (about 2600 RPM at 65 MPH)! The only negatives I can think of are that my 17'' wheels with winter tires won't fit and so far I get a lot more brake dust on all wheels. That's all I can think of right now.
