well the way i look at it is this... your egt's may get to high, but if you don't keep getting on it for a long period of time then you should be fine. you have to get over 1250* for awhile before you melt your pistons. i don't have guages and i use the 5.6k everyday w/ no problems. you should still get guages, but i think you will be fine with the 5.6k. do NOT tow with the 5.6k. i have done it and it pulled great, but i think the egt's got way too high. i would go ahead and run the 10k or 5.6k when driving around town, but not when your towing since you don't have guages.