Ok I'm Confused, need help

[kwin]

I have been gathering parts for a 6.0 swap and I have been looking at buying the No limit Engineering front suspension set up.
It would be going on a 1991 1/2 ton suburban, nice clean truck want it to go faster and handle a little better.
So here is the problem, No Limit will not sell me the kit based on my model year, they say its for up to 87 only, I have explained that the suburbans never changed, same body same suspension up until 1991.
Same answer form No Limit, we do not recommend this set up for a 1991 suburban.

Am I missing something?

Thanks

Keith