The 6TL prices seem to be all over the place IMHO....I always used them in my HMMWV's till the price went through the roof several years ago...these were alway from my supplier, so at that time I went with Optima Red tops and used the adapter trays so they sit in the battery tray meant for the 6TL battery foot print. Over time I found the optimas were junk.
i loose optimas in a truck in about 2-3yrs, I had a set of 6TL's in my slant back last 7yrs!
They do require maint though....now I can get 6TL again for 125.00 ea....so that's what I buy.