SQL 2012 tempdb on SAN or local RAID?

I have set up a SQL 2012 cluster for our future SharePoint 2013 farm, which uses tempdb pretty heavily. Right now we have two servers in the SQL cluster, each with a local drive that hold the OS and SQL install. Our storage team attached some SAN storage for all of the SQL data. Each SQL server has 16 CPU and 256 GB memory. I want to make sure we have optimal performance on this cluster though so I am thinking about trying to convince my manager to supply me with four physical drives for each server that I can use only for tempdb.

Since I do not have the drives yet, I cannot test them to see if they would actually be much faster than the SAN drive. I need to convince my manager to buy them without having actual numbers to give to him. My questions are: 

1. Would moving tempdb off the SAN drive to physical drives definitely be worth it?
2. With four physical drives, would it be a better idea to have a single RAID 10 or two RAID 1 (data on one and logs on the other)?
3. With these RAID setups, if tempdb is split into eight files, would there be contention on the disk that would cause performance issues?

I did run a SQLIO test on the SAN drive. Here is my output. I am not sure if the IO is acceptable as I could not actually find any numbers online of what I should be shooting for. I still need to work with my storage team on adjusting the HBA queue depth, so these numbers will hopefully improve a bit.

C:\Program Files (x86)\SQLIO>sqlio -kW -s360 -frandom -o8 -b64 -LS -Fparam.txt 
sqlio v1.5.SG
using system counter for latency timings, 2636719 counts per second
parameter file used: param.txt
file f:\sqlio_test.dat with 16 threads (0-15) using mask 0x0 (0)
16 threads writing for 360 secs to file f:\sqlio_test.dat
using 64KB random IOs
enabling multiple I/Os per thread with 8 outstanding
using specified size: 100 MB for file: f:\sqlio_test.dat
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:  4569.56
MBs/sec:   285.59
latency metrics:
Min_Latency(ms): 0
Avg_Latency(ms): 27
Max_Latency(ms): 529
histogram:
ms: 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24+
%:  0  0  0  0  0  1  1  1  2  2  2  3  3  4  4  4  5  5  5  5  5  4  3  2 41